Alkali Metals
Lulu Press, Raleigh, N.C. USA
Dr. Pramod Kothari Assistant Professor, Department Of Chemistry Government Post Graduate College, Berinag, District – Pithoragarh Uttarakhand (India)
Copyright Š Creative Commons Attribution-Share Alike 3.0 //creativecommons.org/licenses/by-sa/3.0/ Disclaimer All the material contained in this book is provided for educational and informational purposes only. No responsibility can be taken for any results or outcomes resulting from the use of this material. While every attempt has been made to provide information that is both accurate and effective, the author does not assume any responsibility for the accuracy or use/misuse of this information.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
ii
Preface The alkali metals are a group in the periodic table consisting of the chemical elements lithium (Li), sodium (Na),potassium (K),rubidium (Rb), caesium (Cs), and francium (Fr). This group lies in the s-block of the periodic table as all alkali metals have their outermost electron in an s-orbital. The alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterized homologous behaviour. The alkali metals have very similar properties: they are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. They can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation. Because of their high reactivity, they must be stored under oil to prevent reaction with air, and are found naturally only in salts and never as the free element. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, excluding hydrogen (H), which is nominally a group 1 element but not normally considered to be an alkali metal as it rarely exhibits behaviour comparable to that of the alkali metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones. Dr. Pramod Kothari Assistant Professor, Department Of Chemistry Government Post Graduate College, Berinag, District – Pithoragarh Uttarakhand (India)
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
iii
Table of Contents Alkali Metals ...............................................................................................
1
Alkali Metal oxide ....……………………………………………………………………………….32 Alkali metal Halide………………………………………………………………………………….35 Melting Point……………………………………………………………………………………….. 37 Boiling Point
………………………………………………………………………………………………………………….…..42
Density………………………………………………………………………………………………………………………….…….48 Nunennium...........................................................................................................................61 Hydrogen.................................................................................................65 Ammonium........................................................................................................................... 82 Thallium...................................................................................................85
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
iv
Chapter 1: Alkali Metals All the discovered alkali metals occur in nature: in order of abundance, sodium is the most abundant, followed by potassium, lithium, rubidium, caesium, and finally francium, which is very rare due to its extremely high radioactivity and thus occurs only in traces due to its presence in natural decay chains. Experiments have been conducted to attempt the synthesis of ununennium (Uue), which is likely to be the next member of the group, but they have all met with failure. However, ununennium may not be an alkali metal due to relativistic effects, which are predicted to have a large influence on the chemical properties of superheavy elements; even if it does turn out to be an alkali metal, it is predicted to have some differences in physical and chemical properties from its lighter homologues. Most alkali metals have many different applications. Two of the most well-known applications of the pure elements are rubidium and caesium atomic clocks, of which caesium atomic clocks are the most accurate and precise representation of time. A common application of the compounds of sodium is the sodium-vapour lamp, which emits very efficient light.Table salt, or sodium chloride, has been used since antiquity. Sodium and potassium are also essential elements, having major biological roles as electrolytes, and although the other alkali metals are not essential, they also have various effects on the body, both beneficial and harmful. Characteristics
Chemical
Series of alkali metals, stored in mineral oil to prevent oxidation. ("Natrium" is the German name for sodium.) Like other groups, the known members of this family show patterns in electronic configuration, especially the outermost shells, resulting in trends in chemical behavior: Z Element No. of electrons/shell Electron configuration 3 lithium
2, 1
[He] 2s
1
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 1
11 sodium
2, 8, 1
[Ne] 3s
1
19 potassium 2, 8, 8, 1
[Ar] 4s
1
37 rubidium 2, 8, 18, 8, 1
[Kr] 5s
1
55 caesium 2, 8, 18, 18, 8, 1
[Xe] 6s
87 francium 2, 8, 18, 32, 18, 8, 1
[Rn] 7s
1
1
Most of the chemistry has been observed only for the first five members of the group. The chemistry of francium is not well established due to its extreme radioactivity; thus, the presentation of its properties here is limited.
Caesium reacts explosively with water even at low temperatures All the alkali metals are highly reactive and are never found in elemental forms in nature. Because of this, they are usually stored in mineral oil or kerosene (paraffin oil). They react aggressively with the halogens to form the alkali metal halides, which are white ionic
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 2
crystalline compounds that are all soluble in water except lithium fluoride (LiF). The alkali metals also react with water to form strongly alkaline hydroxides and thus should be handled with great care. The heavier alkali metals react more vigorously than the lighter ones; for example, when dropped into water, caesium produces a larger explosion than potassium. The alkali metals have the lowest first ionisation energies in their respective periods of the periodic table because of their low effective nuclear charge and the ability to attain a noble gas configuration by losing just one electron. The second ionisation energy of all of the alkali metals is very high as it is in a full shell that is also closer to the nucleus; thus, they almost always lose a single electron, forming cations. The alkalides are an exception: they are unstable compounds which contain alkali metals in a −1 oxidation state, which is very unusual as before the discovery of the alkalides, the alkali metals were not expected to be able to form anions and were thought to be able to appear in salts only as cations. The alkalide anions have filled s-subshells, which gives them more stability and allows them to exist. All the stable alkali metals except lithium are known to be able to form alkalides, and the alkalides have much theoretical interest due to their unusual stoichiometry and low ionisation potentials. Alkalides are chemically similar to the electrides, which are salts with trapped electrons acting as anions. A particularly striking example of an alkalide is "inverse + − + − sodium hydride", H Na , as opposed to the usual sodium hydride, Na H : it is unstable in isolation, due to its high energy resulting from the displacement of two electrons from hydrogen to sodium, although several derivatives are predicted to be metastable or stable. The chemistry of lithium shows several differences from that of the rest of the group as the + small Li cation polarises anions and gives its compounds a more covalent character. Lithium and magnesium have a diagonal relationship: because of this, lithium has some similarities to magnesium. For example, lithium forms a stable nitride, a property common among all the alkaline earth metals (magnesium's group) but unique among the alkali metals. In addition, among their respective groups, only lithium and magnesium form covalent organometallic compounds (e.g. LiMe and MgMe2). Lithium fluoride is the only alkali metal halide that is not soluble in water, and lithium hydroxide is the only alkali metal hydroxide that is not deliquescent. Francium is also predicted show some differences due to its high atomic weight, causing its electrons to travel at considerable fractions of the speed of light and thus making relativistic effects more prominent. In contrast to the trend of decreasing electronegativities and ionisation energies of the alkali metals, francium's electronegativity and ionisation energy are predicted to be higher than caesium's due to the relativistic stabilisation of the 7s electrons; also, its atomic radius is expected to be abnormally low. Compounds and reactions
A reaction of 3 pounds (≈ 1.4 kg) of sodium with water All the alkali metals react vigorously or explosively with cold water, producing an aqueous solution of the strongly basic alkali metal hydroxide and releasing hydrogen gas. This reaction becomes more vigorous going down the group: lithium reacts steadily with effervescence, but sodium and potassium can ignite and rubidium and caesium sink in water
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 3
and generate hydrogen gas so rapidly that shock waves form in the water that may shatter glass containers. When an alkali metal is dropped into water, it produces an explosion, of which there are two separate stages. The metal reacts with the water first, breaking the hydrogen bonds in the water and producing hydrogen gas; this takes place faster for the more reactive heavier alkali metals. Second, the heat generated by the first part of the reaction often ignites the hydrogen gas, causing it to burn explosively into the surrounding air. This secondary hydrogen gas explosion produces the visible flame above the bowl of water, lake or other body of water, not the initial reaction of the metal with water (which tends to happen mostly under water). Reaction with the group 14 elements
Side (left) and top (right) views of the graphite intercalation compound KC8 Lithium and sodium react with carbon to form acetylides, Li 2C2 and Na2C2, which can also be obtained by reaction of the metal with acetylene. Potassium, rubidium, and caesium react with graphite; their atoms are intercalated between the hexagonal graphite layers, forming graphite intercalation compounds of formulae MC60 (dark grey, almost black), MC48 (dark grey, almost black), MC36 (blue), MC24 (steel blue), and MC8 (bronze) (M = K, Rb, or Cs). These compounds are over 200 times more electrically conductive than pure graphite, suggesting that the valence electron of the alkali metal is transferred to the graphite layers (e.g. M+ C− 8). Upon heating of KC8, the elimination of potassium atoms results in the conversion in sequence to KC24, KC36, KC48 and finally KC60. KC8 is a very strong reducing agent and is pyrophoric and explodes on contact with water. While the large alkali metals (K, Rb, and Cs) initially form MC8, the smaller ones initially form MC6. When the alkali metals react with the heavier elements in the carbon group, ionic substances with cage-like structures are formed, such as the silicide M4Si4 (M = K, Rb, or Cs), which + 4−4 contains M and tetrahedral Si ions. The chemistry of alkali metal germanides, involving 4− 2−4 4−9 2−9 the germanide ion Ge and other cluster (Zintl) ions such as Ge , Ge , Ge , and 6− [(Ge9)2] , is largely analogous to that of the corresponding silicides. Alkali metal stannides 4− are mostly ionic, sometimes with the stannide ion (Sn ), and sometimes with more complex 4−9 Zintl ions such as Sn , which appears in tetrapotassium nonastannide (K 4Sn9). The
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 4
4−
monatomic plumbide ion (Pb ) is unknown, and indeed its formation is predicted to be 4−9 energetically unfavourable; alkali metal plumbides have complex Zintl ions, such as Pb
Reaction with the pnictogens (alkali metal pnictides)
Unit cell ball-and-stick model of lithium nitride Lithium, the lightest of the alkali metals, is the only alkali metal which reacts with nitrogen at standard conditions, and its nitride is the only stable alkali metal nitride. Nitrogen is an unreactive gas because breaking the strong triple bond in the dinitrogen molecule (N2) requires a lot of energy. The formation of an alkali metal nitride would consume the ionisation + energy of the alkali metal (forming M ions), the energy required to break the triple bond in 3− N2 and the formation of N ions, and all the energy released from the formation of an alkali metal nitride is from the lattice energy of the alkali metal nitride. The lattice energy is maximised with small, highly charged ions; the alkali metals do not form highly charged ions, only forming ions with a charge of +1, so only lithium, the smallest alkali metal, can release enough lattice energy to make the reaction with nitrogen exothermic, forming lithium nitride. The reactions of the other alkali metals with nitrogen would not release enough lattice energy and would thus be endothermic, so they do not form nitrides at standard conditions. (Sodium nitride (Na3N) and potassium nitride (K3N), while existing, are extremely unstable, being prone to decomposing back into their constituent elements, and cannot be produced by reacting the elements with each other at standard conditions.) All the alkali metals react readily with phosphorus and arsenic to form phosphides and arsenides with the formula M3Pn (where M represents an alkali metal and Pn represents a 3− 3− pnictogen). This is due to the greater size of the P and As ions, so that less lattice energy needs to be released for the salts to form. These are not the only phosphides and arsenides of the alkali metals: for example, potassium has nine different known phosphides, with formulae K3P, K4P3, K5P4, KP, K4P6, K3P7, K3P11, KP10.3, and KP15. While most metals form arsenides, only the alkali and alkaline earth metals form mostly ionic arsenides. The structure of Na3As is complex with unusually short Na–Na distances of 328–330 pm which are shorter than in sodium metal, and this indicates that even with these electropositive metals the bonding cannot be straightforwardly ionic. Other alkali metal arsenides not conforming to the formula M3As are known, such as LiAs, which has a metallic lustre and electrical conductivity indicating the presence of some metallic bonding. The antimonides are 3− unstable and reactive as the Sb ion is a strong reducing agent; reaction of them with acids form the toxic and unstable gas stibine (SbH3).Bismuthides are not even wholly ionic; they are intermetallic compounds containing partially metallic and partially ionic bonds. Reaction with the chalcogens (alkali metal chalcogenides)
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 5
See also: Alkali metal oxide
Rb9O 2 cluster, composed of two regular octahedra connected to each other by one face
Cs11O 3 cluster, composed of three regular octahedra where each octahedron is connected to both of the others by one face each. All three octahedra have one edge in common. All the alkali metals react vigorously with oxygen at standard conditions. They form various 2− 2− types of oxides, such as simple oxides (containing the O ion), peroxides (containing the O 2 ion, where there is a single bond between the two oxygen atoms), superoxides (containing −2 the O ion), and many others. Lithium burns in air to form lithium oxide, but sodium reacts with oxygen to form a mixture of sodium oxide and sodium peroxide. Potassium forms a mixture of potassium peroxide and potassium superoxide, while rubidium and caesium form the superoxide exclusively. Their reactivity increases going down the group: while lithium, sodium and potassium merely burn in air, rubidium and caesium are pyrophoric (spontaneously catch fire in air). The smaller alkali metals tend to polarise the more complex anions (the peroxide and superoxide) due to their small size. This attracts the electrons in the more complex anions towards one of its constituent oxygen atoms, forming an oxide ion and an oxygen atom. This causes lithium to form the oxide exclusively on reaction with oxygen at room temperature. This effect becomes drastically weaker for the larger sodium and potassium, allowing them to form the less stable peroxides. Rubidium and caesium, at the bottom of the group, are so large that even the least stable superoxides can form. Because the superoxide releases the most energy when formed, the superoxide is preferentially formed for the larger alkali metals where the more complex anions are not polarised. (The oxides and peroxides for these alkali
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 6
metals do exist, but do not form upon direct reaction of the metal with oxygen at standard + 2− conditions.) In addition, the small size of the Li and O ions contributes to their forming a stable ionic lattice structure. Under controlled conditions, however, all the alkali metals, with the exception of francium, are known to form their oxides, peroxides, and superoxides. The alkali metal peroxides and superoxides are powerful oxidizing agents. Sodium peroxide and potassium superoxide react with carbon dioxide to form the alkali metal carbonate and oxygen gas, which allows them to be used in submarine air purifiers; the presence of water vapour, naturally present in breath, makes the removal of carbon dioxide by potassium superoxide even more efficient. Rubidium and caesium can form even more complicated oxides than the superoxides. Rubidium can form Rb6O and Rb9O2 upon oxidation in air, while caesium forms an immense variety of oxides, such as the ozonide CsO3 and several brightly coloured suboxides, such as Cs7O, Cs4O, Cs11O3, Cs3O (dark-green), CsO, Cs3O2, as well as Cs7O2. The latter may be heated under vacuum to generate Cs2O. The alkali metals can also react analogously with the heavier chalcogens (sulfur, selenium, tellurium, and polonium), and all the alkali metal chalcogenides are known (with the exception of francium's). Reaction with an excess of the chalcogen can similarly result in lower chalcogenides, with chalcogen ions containing chains of the chalcogen atoms in question. For example, sodium can react with sulfur to form the sulfide (Na 2S) and various 2−x polysulfides with the formula Na2Sx (x from 2 to 6), containing the S 2− 2− ions. Due to the basicity of the Se and Te ions, the alkali metal selenides and tellurides are alkaline in solution; when reacted directly with selenium and tellurium, alkali metal polyselenides and polytellurides are formed along with the selenides and tellurides with the 2−x 2−x 2− Se and Te ions. The alkali metal polonides are all ionic compounds containing the Po ion; they are very chemically stable and can be produced by direct reaction of the elements at around 300–400 °C. Reaction with hydrogen and the halogens (alkali metal hydrides and halides) The alkali metals are among the most electropositive elements on the periodic table and thus tend to bond ionically to the most electronegative elements on the periodic table, the halogens, forming salts known as the alkali metal halides. This includes sodium chloride, otherwise known as common salt. The reactivity becomes higher from lithium to caesium and drops from fluorine to iodine. All of the alkali metal halides have the formula MX where M is an alkali metal and X is a halogen. They are all white ionic crystalline solids. All the alkali metal halides are soluble in water except for lithium fluoride (LiF), which is insoluble in water due to its very high lattice enthalpy. The high lattice enthalpy of lithium fluoride is due to the + − small sizes of the Li and F ions, causing the electrostatic interactions between them to be strong. The alkali metals also react similarly with hydrogen to form ionic alkali metal hydrides. Coordination complexes
18-crown-6 coordinating a potassium ion
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 7
Structure of 2.2.2-Cryptand encapsulating a potassium cation (purple). At crystalline state, obtained with an X-ray diffraction. Alkali metal cations do not usually form coordination complexes with simple Lewis bases due + to their low charge of just +1 and their relatively large size; thus the Li ion forms most complexes and the heavier alkali metal ions form less and less. In aqueous solution, the + alkali metal ions exist as octahedral hexahydrate complexes ([M(H 2O)6)] ), with the exception of the lithium ion, which due to its small size forms tetrahedral tetrahydrate complexes + ([Li(H2O)4)] ); the alkali metals form these complexes because their ions are attracted by electrostatic forces of attraction to the polar water molecules. Because of this, anhydrous salts containing alkali metal cations are often used as desiccants. Alkali metals also readily + + form complexes with crown ethers (e.g. 12-crown-4 for Li , 15-crown-5 for Na , and 18+ crown-6 for K ) and cryptands due to electrostatic attraction. Ammonia solutions Unlike most metals, the alkali metals dissolve slowly in liquid ammonia, forming hydrogen gas and the alkali metal amide (MNH2, where M represents an alkali metal). The process may be speeded up by a catalyst. The amide salt is quite insoluble and readily precipitates out of solution, leaving intensely coloured ammonia solutions of the alkali metals. The colour is due to the presence of solvated electrons, which contribute to the high electrical conductivity of these solutions. At low concentrations (below 3 M), the solution is dark blue and has ten times the conductivity of aqueous sodium chloride; at higher concentrations (above 3 M), the solution is copper-coloured and has approximately the conductivity of liquid metals like mercury. In addition to the alkali metal amide salt and solvated electrons, such + ammonia solutions also contain the alkali metal cation (M ), the neutral alkali metal atom (M), − diatomic alkali metal molecules (M2) and alkali metal anions (M ). These are unstable and eventually become the more thermodynamically stable alkali metal amide and hydrogen gas. Solvated electrons are powerful reducing agents and are often used in chemical synthesis. Organometallic chemistry
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 8
Structure of the methyllithium tetramer, (CH3Li)4 Being the smallest alkali metal, lithium forms the widest variety of and most stable organometallic compounds, which are bonded covalently. Organolithium compounds are electrically non-conducting volatile solids or liquids that melt at low temperatures, and tend to form oligomers with the structure (RLi) x where R is the organic group. As the electropositive nature of lithium puts most of the charge density of the bond on the carbon atom, effectively creating a carbanion, organolithium compounds are extremely powerful bases and nucleophiles. For use as bases, butyllithiums are often used and are commercially available. An example of an organolithium compound is methyllithium ((CH 3Li)x), which exists in tetrameric (x = 4) and hexameric (x = 6) forms. The application of organosodium compounds in chemistry is limited in part due to competition from organolithium compounds, which are commercially available and exhibit more convenient reactivity. The principal organosodium compound of commercial importance is sodium cyclopentadienide. Sodium tetraphenylborate can also be classified as an organosodium compound since in the solid state sodium is bound to the aryl groups. Organometallic compounds of the higher alkali metals are even more reactive than organosodium compounds and of limited utility. A notable reagent is Schlosser's base, a mixture of n-butyllithium and potassium tert-butoxide. This reagent reacts with propene to form the compound allylpotassium (KCH2CHCH2). cis-2-Butene and trans-2-butene equilibrate when in contact with alkali metals. Whereas isomerization is fast with lithium and sodium, it is slow with the higher alkali metals. The higher alkali metals also favor the sterically congested conformation. Several crystal structures of organopotassium compounds have been reported, establishing that they, like the sodium compounds, are polymeric. Organosodium, organopotassium, organorubidium and organocaesium compounds are all mostly ionic and are insoluble (or nearly so) in nonpolar solvents. Physical The alkali metals are all silver-coloured except for caesium, which has a golden tint. All are soft and have low densities,melting points, and boiling points. The table below is a summary of the key physical and atomic properties of the alkali metals. Data marked with question marks are either uncertain or are estimations partially based on periodic trends rather than observations. Alkali metal
Standard
Melting
atomic weight point
Boiling point
Density Electronegativity First 3
(g/cm ) (Pauling)
(u)
Atomic Flame
ionisation radius colour energy
(pm) −1
(kJ·mol ) Lithium
6.94(1)
453.69 K, 1615 K,
0.534
0.98
520.2
152
180.54 °C, 1342 °C, 356.97 °F 2448 °F
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 9
Red
test
Sodium
22.98976928(2) 370.87 K, 1156 K,
0.968
0.93
495.8
186
Strong
97.72 °C, 883 °C,
persistent
207.9 °F
orange or
1621 °F
yellow Potassium 39.0983(1)
336.53 K, 1032 K,
0.89
0.82
418.8
227
63.38 °C, 759 °C,
Lilac
or
pink
146.08 °F 1398 °F
Rubidium 85.4678(3)
312.467 K, 961 K,
1.532
0.82
403.0
248
or
39.31 °C, 688 °C,
reddish-
102.76 °F 1270 °F
violet
Caesium 132.9054519(2) 301.59 K, 944 K,
1.93
0.79
375.7
265
28.44 °C, 671 °C,
Francium [223]
Red
83.19 °F
1240 °F
? 300 K,
? 950 K, ? 1.87 ? 0.7
? 27 °C,
? 677 °C,
? 80 °F
? 1250 °F
violet
380
?
Periodic trends The alkali metals are more similar to each other than the elements in any other group are to each other. For instance, when moving down the table, all known alkali metals show increasing atomic radius, decreasing electronegativity, increasing reactivity, and decreasing melting and boiling points. In general, their densities increase when moving down the table, with the exception that potassium is less dense than sodium. Atomic and ionic radii
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Blue
Page 10
?
or
Effective nuclear charge on an atomic electron Atomic and ionic radii of the alkali metals Alkali metal Atomic radius Ionic radius (pm)
(pm)
Lithium
152
68
Sodium
186
98
Potassium
227
133
Rubidium
248
148
Caesium
265
167
The atomic radii of the alkali metals increase going down the group. Because of the shielding effect, when an atom has more than one electron shell, each electron feels electric repulsion from the other electrons as well as electric attraction from the nucleus. In the alkali metals, the outermost electron only feels a net charge of +1, as some of the nuclear charge (which is equal to the atomic number) is cancelled by the inner electrons; the number of inner electrons of an alkali metal is always one less than the nuclear charge. Therefore, the only factor which affects the atomic radius of the alkali metals is the number of electron shells. Since this number increases down the group, the atomic radius must also increase down the group. The ionic radii of the alkali metals are much smaller than their atomic radii. This is because the outermost electron of the alkali metals is in a different electron shell than the inner electrons, and thus when it is removed the resulting atom has one fewer electron shell and is smaller. Additionally, the effective nuclear charge has increased, and thus the electrons are attracted more strongly towards the nucleus and the ionic radius decreases. First ionisation energy
Periodic trend for ionisation energy: each period begins at a minimum for the alkali metals, and ends at a maximum for the noble gases. First ionisation energies of the alkali metals
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 11
Alkali metal
First ionisation
energy
(kJ/mol) Lithium
520.2
Sodium
495.8
Potassium
418.8
Rubidium
403.0
Caesium
375.7
Francium
380
The first ionisation energy of an element or molecule is the energy required to move the most loosely held electron from one mole of gaseous atoms of the element or molecules to form one mole of gaseous ions with electric charge +1. The factors affecting the first ionisation energy are the nuclear charge, the amount of shielding by the inner electrons and the distance from the most loosely held electron from the nucleus, which is always an outer electron in main group elements. The first two factors change the effective nuclear charge the most loosely held electron feels. Since the outermost electron of alkali metals always feel the same effective nuclear charge (+1), the only factor which affects the first ionisation energy is the distance from the outermost electron to the nucleus. Since this distance increases down the group, the outermost electron feels less attraction from the nucleus and thus the first ionisation energy decreases. (This trend is broken in francium due to the relativistic stabilization and contraction of the 7s orbital, bringing francium's valence electron closer to the nucleus than would be expected from non-relativistic calculations. This makes francium's outermost electron feel more attraction from the nucleus, increasing its first ionisation energy slightly beyond that of caesium.) The second ionisation energy of the alkali metals is much higher than the first as the secondmost loosely held electron is part of a fully filled electron shell and is thus difficult to remove. Reactivity The reactivities of the alkali metals increase going down the group. This is the result of a combination of two factors: the first ionisation energies and atomisation energies of the alkali metals. Because the first ionisation energy of the alkali metals decreases down the group, it is easier for the outermost electron to be removed from the atom and participate in chemical reactions, thus increasing reactivity down the group. The atomisation energy measures the strength of the metallic bond of an element, which falls down the group as the atoms increase in radius and thus the metallic bond must increase in length, making the delocalised electrons further away from the attraction of the nuclei of the heavier alkali metals. Adding the atomisation and first ionisation energies gives a quantity closely related to (but not equal to) the activation energy of the reaction of an alkali metal with another substance. This quantity decreases going down the group, and so does the activation energy; thus, chemical reactions can occur faster and the reactivity increases down the group.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 12
Electronegativity
The variation of Pauling electronegativity (y-axis) as one descends the main groups of the periodic table from the second to the sixth period Electronegativities of the alkali metals Alkali metal
Electronegativity
Lithium
0.98
Sodium
0.93
Potassium
0.82
Rubidium
0.82
Caesium
0.79
Francium
? 0.7
Electronegativity is a chemical property that describes the tendency of an atom or a functional group to attract electrons (or electron density) towards itself. If the bond between sodium and chlorine in sodium chloride were covalent, the pair of shared electrons would be attracted to the chlorine because the effective nuclear charge on the outer electrons is +7 in chlorine but is only +1 in sodium. The electron pair is attracted so close to the chlorine atom that they are practically transferred to the chlorine atom (an ionic bond). However, if the sodium atom was replaced by a lithium atom, the electrons will not be attracted as close to the chlorine atom as before because the lithium atom is smaller, making the electron pair more strongly attracted to the closer effective nuclear charge from lithium. Hence, the larger alkali metal atoms (further down the group) will be less electronegative as the bonding pair is less strongly attracted towards them. Because of the higher electronegativity of lithium, some of its compounds have a more covalent character. For example, lithium iodide (LiI) will dissolve in organic solvents, a
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 13
property of most covalent compounds.Lithium fluoride (LiF) is the only alkali halide that is not soluble in water, and lithium hydroxide (LiOH) is the only alkali metal hydroxide that is not deliquescent. Melting and boiling points Melting and boiling points of the alkali metals Alkali metal Melting point
Boiling point
Lithium
453.69 K (180.54 °C) 1615 K (1342 °C)
Sodium
370.87 K (97.72 °C) 1156 K (883 °C)
Potassium
336.53 K (63.38 °C) 1032 K (759 °C)
Rubidium
312.46 K (39.31 °C) 961 K (688 °C)
Caesium
301.59 K (28.44 °C) 944 K (671 °C)
Francium
? 300 K (? 27 °C)
? 950 K (? 677 °C)
The melting point of a substance is the point where it changes state from solid to liquid while the boiling point of a substance (in liquid state) is the point where the vapor pressure of the liquid equals the environmental pressure surrounding the liquid and all the liquid changes state to gas. As a metal is heated to its melting point, the metallic bonds keeping the atoms in place weaken so that the atoms can move around, and the metallic bonds eventually break completely at the metal's boiling point. Therefore, the falling melting and boiling points of the alkali metals indicate that the strength of the metallic bonds of the alkali metals decreases down the group. This is because metal atoms are held together by the electromagnetic attraction from the positive ions to the delocalised electrons. As the atoms increase in size going down the group (because their atomic radius increases), the nuclei of the ions move further away from the delocalised electrons and hence the metallic bond becomes weaker so that the metal can more easily melt and boil, thus lowering the melting and boiling points. (The increased nuclear charge is not a relevant factor due to the shielding effect.) Density Densities of the alkali metals 3
Alkali metal Density (g/cm ) Lithium
0.534
Sodium
0.968
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 14
Potassium
0.89
Rubidium
1.532
Caesium
1.93
Francium
? 1.87
The alkali metals all have the same crystal structure (body-centred cubic) and thus the only relevant factors are the number of atoms that can fit into a certain volume and the mass of one of the atoms, since density is defined as mass per unit volume. The first factor depends on the volume of the atom and thus the atomic radius, which increases going down the group; thus, the volume of an alkali metal atom increases going down the group. The mass of an alkali metal atom also increases going down the group. Thus, the trend for the densities of the alkali metals depends on their atomic weights and atomic radii; if figures for these two factors are known, the ratios between the densities of the alkali metals can then be calculated. The resultant trend is that the densities of the alkali metals increase down the table, with an exception at potassium. Due to having the lowest atomic weight of all the elements in their period and having the largest atomic radius for their periods, the alkali metals are the least dense metals in the periodic table. Lithium, sodium, and potassium are the only three metals in the periodic table that are less dense than water. Nuclear Primordial isotopes of the alkali metals Z Alkali metal Stable Decays unstable: italics odd-odd isotopes coloured pink 3 lithium
2
—
7Li
11 sodium
1
—
23Na
19 potassium
2
1
39K
41K
37 rubidium
1
1
85Rb
87Rb
55 caesium
1
—
133Cs
87 francium
—
—
No primordial isotopes
6Li
40K
All the alkali metals have odd atomic numbers; hence, their isotopes must be either odd-odd (both proton and neutron number are odd) or odd-even (proton number is odd, but neutron number is even). Odd-odd nuclei have even mass numbers, while odd-even nuclei have odd mass numbers. Odd-odd primordial nuclides are rare because most odd-odd nuclei are
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 15
highly unstable with respect to beta decay, because the decay products are even-even, and are therefore more strongly bound, due to nuclear pairing effects. Due to the great rarity of odd-odd nuclei, almost all the primordial isotopes of the alkali metals are odd-even (the exceptions being the light stable isotope lithium-6 and the longlived radioisotope potassium-40). For a given odd mass number, there can be only a single beta-stable nuclide, since there is not a difference in binding energy between even-odd and odd-even comparable to that between even-even and odd-odd, leaving other nuclides of the same mass number (isobars) free to beta decay toward the lowest-mass nuclide. An effect of the instability of an odd number of either type of nucleons is that odd-numbered elements, such as the alkali metals, tend to have fewer stable isotopes than even-numbered elements. Of the 26 monoisotopic elements that have only a single stable isotope, all but one have an odd atomic number and all but one also have an even number of neutrons. Beryllium is the single exception to both rules, due to its low atomic number. All of the alkali metals except lithium and caesium have at least one naturally occurring radioisotope: sodium-22 and sodium-24 are trace radioisotopes produced cosmogenically, potassium-40 and rubidium-87 have very long half-lives and thus occur naturally, and all isotopes of francium are radioactive. Caesium was also thought to be radioactive in the early 20th century, although it has no naturally occurring radioisotopes. (Francium had not been discovered yet at that time.) The natural radioisotope of potassium, potassium-40, makes up about 0.012% of natural potassium, and thus natural potassium is weakly radioactive. This natural radioactivity became a basis for a mistaken claim of the discovery for element 87 (the next alkali metal after caesium) in 1925. Caesium-137, with a half-life of 30.17 years, is one of the two principal medium-lived fission products, along with strontium-90, which are responsible for most of the radioactivity of spent nuclear fuel after several years of cooling, up to several hundred years after use. It 137 constitutes most of the radioactivity still left from the Chernobyl accident. Cs undergoes high-energy beta decay and eventually becomes stable barium-137. It is a strong emitter of 137 gamma radiation. Cs has a very low rate of neutron capture and cannot be feasibly 137 disposed of in this way, but must be allowed to decay. Cs has been used as a tracer in hydrologic studies, analogous to the use of tritium. Small amounts of caesium-134 and caesium-137 were released into the environment during nearly all nuclear weapon tests and some nuclear accidents, most notably the Goiânia accident and the Chernobyl disaster. As of 2005, caesium-137 is the principal source of radiation in the zone of alienation around the Chernobyl nuclear power plant. Extensions
Empirical (Na–Cs, Mg–Ra) and predicted (Fr–Uhp, Ubn–Uhh) atomic radius of the alkali and
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 16
alkaline earth metals from the third to the ninth period, measured in angstroms Although francium is the heaviest alkali metal that has been discovered, there has been some theoretical work predicting the physical and chemical characteristics of the hypothetical heavier alkali metals. Being the first period 8 element, the undiscovered element ununennium (element 119) is predicted to be the next alkali metal after francium and behave much like their lighter congeners; however, it is also predicted to differ from the lighter alkali metals in some properties. Its chemistry is predicted to be closer to that of potassium or rubidium instead of caesium or francium. This is unusual as periodic trends, ignoring relativistic effects would predict ununennium to be even more reactive than caesium and francium. This lowered reactivity is due to the relativistic stabilisation of ununennium's valence electron, increasing ununennium's first ionisation energy and decreasing the metallic and ionic radii; this effect is already seen for francium. This assumes that ununennium will behave chemically as an alkali metal, which, although likely, may not be true due to relativistic effects. The relativistic stabilisation of the 8s orbital also increases ununennium's electron affinity far beyond that of caesium and francium; indeed, ununennium is expected to have an electron affinity higher than all the alkali metals lighter than it. Relativistic effects also cause a very large drop in the polarisability of ununennium. On the other hand, ununennium is predicted to continue the trend of melting points decreasing going down the group, being expected to have a melting point between 0 °C and 30 °C.
Empirical (Na–Fr) and predicted (Uue) electron affinity of the alkali metals from the third to the eighth period, measured in electron volts The stabilisation of ununennium's valence electron and thus the contraction of the 8s orbital cause its atomic radius to be lowered to 240 pm, very close to that of rubidium (247 pm), so that the chemistry of ununennium in the +1 oxidation state should be more similar to the chemistry of rubidium than to that of francium. On the other hand, the ionic radius of the + + Uue ion is predicted to be larger than that of Rb , because the 7p orbitals are destabilised and are thus larger than the p-orbitals of the lower shells. Ununennium may also show the +3 oxidation state, which is not seen in any other alkali metal, in addition to the +1 oxidation state that is characteristic of the other alkali metals and is also the main oxidation state of all
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 17
the known alkali metals: this is because of the destabilisation and expansion of the 7p 3/2 spinor, causing its outermost electrons to have a lower ionisation energy than what would otherwise be expected. Indeed, many ununennium compounds are expected to have a large covalent character, due to the involvement of the 7p3/2 electrons in the bonding.
Empirical (Na–Fr, Mg–Ra) and predicted (Uue–Uhp, Ubn–Uhh) ionisation energy of the alkali and alkaline earth metals from the third to the ninth period, measured in electron volts Not as much work has been done predicting the properties of the alkali metals beyond ununennium. Although a simple extrapolation of the periodic table would put element 169, unhexennium, under ununennium, Dirac-Fock calculations predict that the next alkali metal after ununennium may actually be element 165, unhexpentium, which is predicted to have 18 14 10 2 2 1 the electron configuration [Uuo] 5g 6f 7d 8s 8p1/2 9s . Further calculations show that unhexpentium would follow the trend of increasing ionisation energy beyond caesium, having an ionisation energy comparable to that of sodium, and that it should also continue the trend of decreasing atomic radii beyond caesium, having an atomic radius comparable to that of potassium. However, the 7d electrons of unhexpentium may also be able to participate in chemical reactions along with the 9s electron, possibly allowing oxidation states beyond +1 and perhaps even making unhexpentium behave more like a boron group element than an alkali metal. The probable properties of the alkali metals beyond unhexpentium have not been explored yet as of 2012. In periods 8 and above of the periodic table, relativistic and shell-structure effects become so strong that extrapolations from lighter congeners become completely inaccurate. In addition, the relativistic and shell-structure effects (which stabilise the sorbitals and destabilise and expand the d-, f-, and g-orbitals of higher shells) have opposite effects, causing even larger difference between relativistic and non-relativistic calculations of the properties of elements with such high atomic numbers. Due to the alkali and alkaline earth metals both being s-block elements, these predictions for the trends and properties of ununennium and unhexpentium also mostly apply to the corresponding alkaline earth metals unbinilium (Ubn) and unhexhexium (Uhh).
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 18
Other similar substances
Hydrogen
Hydrogen gas glowing in a discharge tube The element hydrogen, with one electron per neutral atom, is usually placed at the top of Group 1 of the periodic table for convenience, but hydrogen is not normally considered to be an alkali metal; when it is considered to be an alkali metal, it is because of its atomic properties and not its chemical properties. Under typical conditions, pure hydrogen exists as a diatomic gas consisting of two atoms per molecule (H2); however, the alkali metals only form diatomic molecules (such as dilithium, Li2) at high temperatures, when they are in the gaseous state. Hydrogen, like the alkali metals, has one valence electron and reacts easily with the halogens, but the similarities end there. Its placement above lithium is primarily due to its electron configuration and not its chemical properties. It is sometimes placed above carbon due to their similar electronegativities or fluorine due to their similar chemical properties. The first ionisation energy of hydrogen (1312.0 kJ/mol) is much higher than that of the alkali metals. As only one additional electron is required to fill in the outermost shell of the hydrogen atom, hydrogen often behaves like a halogen, forming the negative hydride ion, and is sometimes considered to be a halogen. (The alkali metals can also form negative ions, known as alkalides, but these are little more than laboratory curiosities, being unstable.) Under extremely high pressures, such as those found at the cores of Jupiter and Saturn, hydrogen does become metallic and behaves like an alkali metal; in this phase, it is known as metallic hydrogen. Ammonium +
The ammonium ion (NH4 ) has very similar properties to the heavier alkali metals, acting as an alkali metal intermediate between potassium and rubidium, and is often considered a close relative. For example, most alkali metal salts are soluble in water, a property which + ammonium salts share. Ammonium is expected to behave stably as a metal (NH4 4 ions in a sea of electrons) at very high pressures (though less than the typical pressure where transitions from insulating to metallic behaviour occur around, 100 GPa), and could possibly occur inside the ice giants Uranus and Neptune, which may have significant impacts on their interior magnetic fields. It has been estimated that the transition from a mixture of ammonia and dihydrogen molecules to metallic ammonium may occur at pressures just below 25 GPa.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 19
Thallium
Very pure thallium pieces in a glass ampoule, stored under argon gas Thallium displays the +1 oxidation state that all the known alkali metals display, and thallium compounds with thallium in its +1 oxidation state closely resemble the corresponding + + potassium or silver compounds due to the similar ionic radii of the Tl (164 pm), K (152 pm) + and Ag (129 pm) ions. It was sometimes considered an alkali metal in continental Europe (but not in England) in the years immediately following its discovery, and was placed just after caesium as the sixth alkali metal in Dmitri Mendeleev's 1869 periodic table and Julius Lothar Meyer's 1868 periodic table. (Mendeleev's 1871 periodic table and Meyer's 1870 periodic table put thallium in its current position in the boron group and leave the space below caesium blank.) However, thallium also displays the oxidation state +3, which no known alkali metal displays (although ununennium, the undiscovered seventh alkali metal, is predicted to possibly display the +3 oxidation state). The sixth alkali metal is now considered to be francium. History
Etymology The alkali metals are so called because their hydroxides are all strong alkalis when dissolved in water. Discovery
Lithium
Petalite, the lithium mineral from which lithium was first isolated Petalite (LiAlSi4O10) was discovered in 1800 by the Brazilian chemist JosĂŠ BonifĂĄcio de Andrada in a mine on the island of UtĂś, Sweden. However, it was not until 1817 that Johan
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 20
August Arfwedson, then working in the laboratory of the chemist Jöns Jacob Berzelius, detected the presence of a new element while analyzing petalite ore. This new element formed compounds similar to those of sodium and potassium, though its carbonate and hydroxide were less soluble in water and more alkaline than the other alkali metals. Berzelius gave the unknown material the name "lithion/lithina", from the Greek word λιθoς (transliterated as lithos, meaning "stone"), to reflect its discovery in a solid mineral, as opposed to potassium, which had been discovered in plant ashes, and sodium, which was known partly for its high abundance in animal blood. He named the metal inside the material "lithium". Sodium
Caustic soda (sodium hydroxide), the sodium compound from which sodium was first isolated Sodium compounds have been known since ancient times; salt (sodium chloride) has been an important commodity in human activities, as testified by the English word salary, referring to salarium, the wafers of salt sometimes given to Roman soldiers along with their other [citation needed] wages. In medieval Europe a compound of sodium with the Latin name of [citation needed] sodanum was used as a headache remedy. Pure sodium was not isolated until 1807 by Humphry Davy through the electrolysis of caustic soda (now called sodium hydroxide), a very similar method to the one used to isolate potassium earlier that year. Potassium
Caustic potash (potassium hydroxide), the potassium compound from which potassium was first isolated While potash has been used since ancient times, it was not understood for most of its history to be a fundamentally different substance from sodium mineral salts. Georg Ernst Stahl obtained experimental evidence which led him to suggest the fundamental difference of
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 21
sodium and potassium salts in 1702, and Henri Louis Duhamel du Monceau was able to prove this difference in 1736. The exact chemical composition of potassium and sodium compounds, and the status as chemical element of potassium and sodium, was not known then, and thus Antoine Lavoisier did include the alkali in his list of chemical elements in 1789. Pure potassium was first isolated in 1807 in England by Sir Humphry Davy, who derived it from caustic potash (KOH, potassium hydroxide) by the use of electrolysis of the molten salt with the newly invented voltaic pile. Potassium was the first metal that was isolated by electrolysis. Later that same year, Davy reported extraction of sodium from the similar substance caustic soda (NaOH, lye) by a similar technique, demonstrating the elements, and thus the salts, to be different. Rubidium
Lepidolite, the rubidium mineral from which rubidium was first isolated Rubidium was discovered in 1861 in Heidelberg, Germany by Robert Bunsen and Gustav Kirchhoff, the first people to suggest finding new elements by spectrum analysis, in the mineral lepidolite through the use of a spectroscope. Because of the bright red lines in its emission spectrum, they chose a name derived from the Latin word rubidus, meaning dark red or bright red. Rubidium's discovery succeeded that of caesium, also discovered by Bunsen and Kirchhoff through spectroscopy. Caesium In 1860, Robert Bunsen and Gustav Kirchhoff discovered caesium in the mineral water from D端rkheim, Germany. Due to the bright-blue lines in its emission spectrum, they chose a name derived from the Latin word caesius, meaning sky-blue. Caesium was the first element to be discovered spectroscopically, only one year after the invention of the spectroscope by Bunsen and Kirchhoff. Francium There were at least four erroneous and incomplete discoveries before Marguerite Perey of the Curie Institute in Paris, France discovered francium in 1939 by purifying a sample of actinium-227, which had been reported to have a decay energy of 220 keV. However, Perey noticed decay particles with an energy level below 80 keV. Perey thought this decay activity might have been caused by a previously unidentified decay product, one that was separated during purification, but emerged again out of the pure actinium-227. Various tests eliminated the possibility of the unknown element being thorium, radium, lead, bismuth, or thallium. The new product exhibited chemical properties of an alkali metal (such as coprecipitating with caesium salts), which led Perey to believe that it was element 87, caused by the alpha decay of actinium-227. Perey then attempted to determine the proportion of beta decay to alpha
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 22
decay in actinium-227. Her first test put the alpha branching at 0.6%, a figure that she later revised to 1%. It was the last element discovered in nature, rather than by synthesis. Eka-francium The next element below francium (eka-francium) is very likely to be ununennium (Uue), element 119, although this is not completely certain due to relativistic effects. The synthesis of ununennium was first attempted in 1985 by bombarding a target of einsteinium-254 with calcium-48 ions at the superHILAC accelerator at Berkeley, California. No atoms were identified, leading to a limiting yield of 300 nb. 254 99Es
+
48
20Ca
→
302
119Uue* → no atoms It is highly unlikely that this reaction will be able to create any atoms of ununennium in the 254 near future, given the extremely difficult task of making sufficient amounts of Es, which is favoured for production of ultraheavy elements because of its large mass, relatively long halflife of 270 days, and availability in significant amounts of several micrograms, to make a large enough target to increase the sensitivity of the experiment to the required level; einsteinium has not been found in nature and has only been produced in laboratories. However, given that ununennium is only the first period 8 element on the extended periodic table, it may well be discovered in the near future through other reactions; indeed, another attempt to synthesise ununennium by bombarding a berkelium target with titanium ions is under way at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany. Currently, none of the period 8 elements have been discovered yet, and it is also possible, due to drip instabilities, that only the lower period 8 elements, up to around element 128, are physically possible. No attempts at synthesis have been made for any heavier alkali metals, such as unhexpentium, due to their extremely high atomic number.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 23
Occurrence
In the Solar System
Estimated abundances of the chemical elements in the Solar system. Hydrogen and helium are most common, from the Big Bang. The next three elements (lithium, beryllium, and boron) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar-produced elements are: (1) an alternation of abundance in elements as they have even or odd atomic numbers, and (2) a general decrease in abundance, as elements become heavier. Iron is especially common because it represents the minimum energy nuclide that can be made by fusion of helium in supernovae. The Oddo-Harkins rule holds that elements with even atomic numbers are more common that those with odd atomic numbers, with the exception of hydrogen. This rule argues that elements with odd atomic numbers have one unpaired proton and are more likely to capture another, thus increasing their atomic number. In elements with even atomic numbers, protons are paired, with each member of the pair offsetting the spin of the other, enhancing stability. All the alkali metals have odd atomic numbers and they are not as common as the elements with even atomic numbers adjacent to them (the noble gases and the alkaline earth metals) in the Solar System. The heavier alkali metals are also less abundant than the lighter ones as the alkali metals from rubidium onward can only be synthesized in supernovae and not in stellar nucleosynthesis. Lithium is also much less abundant than sodium and potassium as it is poorly synthesized in both Big Bang nucleosynthesis and in stars: the Big Bang could only produce trace quantities of lithium, beryllium and boron due to the absence of a stable nucleus with 5 or 8 nucleons, and stellar nucleosynthesis could only pass this bottleneck by the triple-alpha process, fusing three helium nuclei to form carbon, and skipping over those three elements.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 24
On Earth
Spodumene, an important lithium mineral The Earth formed from the same cloud of matter that formed the Sun, but the planets acquired different compositions during the formation and evolution of the solar system. In turn, the natural history of the Earth caused parts of this planet to have differing 24 concentrations of the elements. The mass of the Earth is approximately 5.98Ă—10 kg. It is composed mostly of iron (32.1%), oxygen (30.1%), silicon (15.1%), magnesium (13.9%), sulfur (2.9%), nickel (1.8%), calcium (1.5%), and aluminium (1.4%); with the remaining 1.2% consisting of trace amounts of other elements. Due to mass segregation, the core region is believed to be primarily composed of iron (88.8%), with smaller amounts of nickel (5.8%), sulfur (4.5%), and less than 1% trace elements. The alkali metals, due to their high reactivity, do not occur naturally in pure form in nature. They are lithophiles and therefore remain close to the Earth's surface because they combine readily with oxygen and so associate strongly with silica, forming relatively low-density minerals that do not sink down into the Earth's core. Potassium, rubidium and caesium are also incompatible elements due to their low ionic radii. Sodium and potassium are very abundant in earth, both being among the ten most common elements in Earth's crust; sodium makes up approximately 2.6% of the Earth's crust measured by weight, making it the sixth most abundant element overall and the most abundant alkali metal. Potassium makes up approximately 1.5% of the Earth's crust and is the seventh most abundant element. Sodium is found in many different minerals, of which the most common is ordinary salt (sodium chloride), which occurs in vast quantities dissolved in seawater. Other solid deposits include halite, amphibole, cryolite, nitratine, and zeolite. Lithium, due to its relatively low reactivity, can be found in seawater in large amounts; it is estimated that seawater is approximately 0.14 to 0.25 parts per million (ppm) or 25 micromolar. Rubidium is approximately as abundant as zinc and more abundant than copper. It occurs naturally in the minerals leucite, pollucite, carnallite, zinnwaldite, and lepidolite. Caesium is more abundant than some commonly known elements, such as antimony, cadmium, tin, and tungsten, but is much less abundant than rubidium. Francium-223, the only naturally occurring isotope of francium, is the product of the alpha decay of actinium-227 and can be found in trace amounts in uranium and thorium minerals.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 25
18
In a given sample of uranium, there is estimated to be only one francium atom for every 10 uranium atoms. It has been calculated that there is at most 30 g of francium in the earth's crust at any time, due to its extremely short half-life of 22 minutes. Production and isolation
Salt flats are rich in lithium, such as these in Salar del Hombre Muerto, Argentina (left) and Uyuni, Bolivia (right). The lithium-rich brine is concentrated by pumping it into solar evaporation ponds (visible in Argentina image). The production of pure alkali metals is difficult due to their extreme reactivity with commonly used substances, such as water. The alkali metals are so reactive that they cannot be displaced by other elements and must be isolated through high-energy methods such as electrolysis. Lithium salts have to be extracted from the water of mineral springs, brine pools, and brine deposits. The metal is produced electrolytically from a mixture of fused lithium chloride and potassium chloride. Potassium occurs in many minerals, such as sylvite (potassium chloride). It is occasionally produced through separating the potassium from the chlorine in potassium chloride, but is more often produced through electrolysis of potassium hydroxide, found extensively in places such as Canada, Russia, Belarus, Germany, Israel, United States, and Jordan, in a method similar to how sodium was produced in the late 1800s and early 1900s. It can also be produced from seawater. Sodium occurs mostly in seawater and dried seabed, but is now produced through electrolysis of sodium chloride by lowering the melting point of the substance to below 700 째C through the use of a Downs cell. Extremely pure sodium can be produced through the thermal decomposition of sodium azide.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 26
This sample of uraninite contains about 100,000 atoms (3.3×10
−20
g) of francium-223 at any
given time. For several years in the 1950s and 1960s, a by-product of the potassium production called Alkarb was a main source for rubidium. Alkarb contained 21% rubidium while the rest was potassium and a small fraction of caesium. Today the largest producers of caesium, for example the Tanco Mine, Manitoba, Canada, produce rubidium as by-product from pollucite. Today, a common method for separating rubidium from potassium and caesium is the fractional crystallization of a rubidium and caesium alum (Cs, Rb)Al(SO 4)2·12H2O, which yields pure rubidium alum after approximately 30 different reactions. The limited applications and the lack of a mineral rich in rubidium limits the production of rubidium compounds to 2 to 4 tonnes per year. Caesium, however, is not produced from the above reaction. Instead, the mining of pollucite ore is the main method of obtaining pure caesium, extracted from the ore mainly by three methods: acid digestion, alkaline decomposition, and direct reduction. Francium-223, the only naturally occurring isotope of francium, is produced naturally as the product of the alpha decay of actinium-227. Francium can be found in trace amounts in uranium and thorium minerals; it has been calculated that at most there are 30 g of francium in the earth's crust at any given time. As a result of its extreme rarity in nature, most francium 197 18 210 is synthesized in the nuclear reaction Au + O → Fr + 5 n, yielding francium-209, francium-210, and francium-211. The greatest quantity of francium ever assembled to date is about 300,000 neutral atoms, which were synthesized using the nuclear reaction given above. From their silicate ores, all the alkali metals may be obtained the same way: sulfuric acid is first used to dissolve the desired alkali metal ion and aluminium(III) ions from the ore (leaching), whereupon basic precipitation removes aluminium ions from the mixture by precipitating it as the hydroxide. The remaining insoluble alkali metal carbonate is then precipitated selectively; the salt is then dissolved in hydrochloric acid. The result is then left to evaporate and the alkali metal can then be isolated through electrolysis. Lithium and sodium are typically isolated through electrolysis from their liquid chlorides, with calcium chloride typically added to lower the melting point of the mixture. The heavier alkali metals, however, is more typically isolated in a different way, where a reducing agent (typically sodium for potassium and magnesium or calcium for the heaviest alkali metals) is used to reduce the alkali metal chloride. The liquid or gaseous product (the alkali metal) then undergoes fractional distillation for purification.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 27
Applications All of the discovered alkali metals excluding francium have many applications. Lithium is often used in batteries, and lithium oxide can help process silica. Lithium can also be used to make lubricating greases, air treatment, and aluminium production. Pure sodium has many applications, including use in sodium-vapour lamps, which produce very efficient light compared to other types of lighting, and can help smooth the surface of other metals. Sodium compounds have many applications as well, the most well-known [citation needed] compound being table salt. Sodium is also used in soap as salts of fatty [citation needed] acids. Potassium compounds are often used as fertilisers as potassium is an important element for [citation needed] plant nutrition. Other potassium ions are often used to hold anions. Potassium hydroxide is a very strong base, and is used to control the pH of various substances.
FOCS 1, a caesium atomic clock in Switzerland Rubidium and caesium are often used in atomic clocks. Caesium atomic clocks are extraordinarily accurate; if a clock had been made at the time of the dinosaurs, it would be off by less than four seconds (after 80 million years). For that reason, caesium atoms are used as the definition of the second. Rubidium ions are often used in purple fireworks, and caesium is often used in drilling fluids in the petroleum industry. Francium has no commercial applications, but because of francium's relatively simple atomic structure, among other things, it has been used in spectroscopy experiments, leading to more information regarding energy levels and the coupling constants between subatomic particles. Studies on the light emitted by laser-trapped francium-210 ions have provided accurate data on transitions between atomic energy levels, similar to those predicted by quantum theory.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 28
Biological role and precautions
Lithium carbonate Lithium naturally only occurs in traces in biological systems and has no known biological role, but does have effects on the body when ingested.Lithium carbonate is used as a mood stabiliser in psychiatry to treat bipolar disorder (manic-depression) in daily doses of about 0.5 to 2 grams, although there are side-effects. Excessive ingestion of lithium causes drowsiness, slurred speech and vomiting, among other symptoms, and poisons the central nervous system, which is dangerous as the required dosage of lithium to treat bipolar disorder is only slightly lower than the toxic dosage. Its biochemistry, the way it is handled by the human body and studies using rats and goats suggest that it is an essential trace element, although the natural biological function of lithium in humans has yet to be identified. Sodium and potassium occur in all known biological systems, generally functioning as electrolytes inside and outside cells. Sodium is an essential nutrient that regulates blood volume, blood pressure, osmotic equilibrium and pH; the minimum physiological requirement for sodium is 500 milligrams per day.Sodium chloride (also known as common salt) is the principal source of sodium in the diet, and is used as seasoning and preservative, such as for pickling and jerky; most of it comes from processed foods. The DRI for sodium is 1.5 grams per day, but most people in the United States consume more than 2.3 grams per day, the minimum amount that promotes hypertension; this in turn causes 7.6 million premature deaths worldwide. Potassium is the major cation (positive ion) inside animal cells, while sodium is the major cation outside animal cells. The concentration differences of these charged particles causes a difference in electric potential between the inside and outside of cells, known as the membrane potential. The balance between potassium and sodium is maintained by ion pumps in the cell membrane. The cell membrane potential created by potassium and sodium ions allows the cell to generate an action potential—a "spike" of electrical discharge. The ability of cells to produce electrical discharge is critical for body functions such as neurotransmission, muscle contraction, and heart function.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 29
A wheel type radiotherapy device which has a long collimator to focus the radiation into a narrow beam. The caesium-137 chloride radioactive source is the blue square, and gamma rays are represented by the beam emerging from the aperture. This was the radiation source involved in the Goiânia accident, containing about 93 grams of caesium-137 chloride. Rubidium has no known biological role, but may help stimulate metabolism, and, similarly to caesium, replace potassium in the body causing potassium deficiency. Caesium compounds are rarely encountered by most people, but most caesium compounds are mildly toxic because of chemical similarity of caesium to potassium, allowing the caesium to replace the potassium in the body, causing potassium deficiency. Exposure to large amounts of caesium compounds can cause hyperirritability and spasms, but as such amounts would not ordinarily be encountered in natural sources, caesium is not a major chemical environmental pollutant. The median lethal dose (LD50) value for caesium chloride in mice is 2.3 g per kilogram, which is comparable to the LD50 values of potassium chloride and sodium chloride. Caesium chloride has been promoted as an alternative cancer therapy, but has been linked to the deaths of over 50 patients, on whom it was used as part of a scientifically unvalidated cancer treatment.Radioisotopes of caesium require special precautions: the improper handling of caesium-137 gamma ray sources can lead to release of this radioisotope and radiation injuries. Perhaps the best-known case is the Goiânia accident of 1987, in which an improperly-disposed-of radiation therapy system from an abandoned clinic in the city of Goiânia, Brazil, was scavenged from a junkyard, and the glowing caesium salt sold to curious, uneducated buyers. This led to four deaths and serious injuries from radiation exposure. Together with caesium-134, iodine-131, and strontium-90, caesium-137 was among the isotopes distributed by the Chernobyl disaster which constitute the greatest risk to health. Francium has no biological role and is most likely to be toxic due to its extreme radioactivity, causing radiation poisoning, but since the greatest quantity of francium ever assembled to date is about 300,000 neutral atoms, it is unlikely that most people will ever encounter francium. Further reading
Bauer, Brent A., Robert Houlihan, Michael J. Ackerman, Katya Johnson, and Himeshkumar Vyas (2006). "Acquired Long QT Syndrome Secondary to Cesium Chloride Supplement". Journal of Alternative and Complementary Medicine 12 (10): 1011–1014. doi:10.1089/acm.2006.12.1011. PMID 17212573.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 30
Chapter 2: Alkali metal oxide
A sample of sodium peroxide. The alkali metals react with oxygen to form several different compounds: suboxides, oxides, peroxides, superoxides, and ozonides. They all react violently with water. Alkali metal suboxides
Structure of undecacaesium trioxide.
Hexarubidium monoxide (Rb6O)
Nonarubidium dioxide (Rb9O2)
Caesium monoxide (CsO)
Tricaesium monoxide (Cs3O) is a dark green solid.
Tetracaesium monoxide (Cs4O)
Heptacaesium monoxide (Cs7O)
Tricaesium dioxide (Cs3O2)
Heptacaesium dioxide (Cs7O2)
Undecacaesium trioxide (Cs11O3)
Undecacaesium monorubidium trioxide (Cs11RbO3)
Undecacaesium dirubidium trioxide (Cs11Rb2O3)
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 31
Undecacaesium trirubidium trioxide (Cs11Rb3O3)
Alkali metal oxides
Crystal structure of rubidium oxide.
Lithium oxide (Li2O) is the lightest alkali metal oxide and a white solid. It melts at 1570°C.
Sodium oxide (Na2O) is a white solid that melts at 1132°C and decomposes at 1950°C. It is a component of glass.
Potassium oxide (K2O) is a pale yellow solid that decomposes at 350°C.
Rubidium oxide (Rb2O) is a yellow solid that melts at 500°C.
Caesium oxide (Cs2O) is a yellow-orange solid that melts at 490°C.
Alkali metal peroxides
Crystal structure of sodium peroxide.
Lithium peroxide (Li2O2) is a white solid that melts at 195°C. It reacts with carbon dioxide to form lithium carbonate and oxygen and was used as a carbon dioxide scrubber on the Apollo spacecraft.
Sodium peroxide (Na2O2) is a pale yellow solid that melts at 460°C and boils at 657°C.
Potassium peroxide (K2O2) is a yellow solid that melts at 490°C.
Rubidium peroxide (Rb2O2) is produced when rubidium stands in air.
Caesium peroxide (Cs2O2) is produced by the decomposition of caesium oxide above 400°C.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 32
Alkali metal superoxides
Crystal structure of potassium superoxide.
Lithium superoxide (LiO2) has only been isolated in matrix isolation at 15 K.
Sodium superoxide (NaO2) is a yellow-orange solid that melts at 551.7°C. It is made by the high-pressure oxidation of sodium peroxide.
Potassium superoxide (KO2) is a yellow solid that decomposes at 560°C. It is used as a CO2 scrubber, H2O dehumidifier and O2 generator in rebreathers, spacecraft, submarines and spacesuit life support systems.
Rubidium superoxide (RbO2) is produced when rubidium burns in air.
Caesium superoxide (CsO2) is produced when caesium burns in air.
Alkali metal ozonides
Lithium ozonide (LiO3) is a red solid which is produced from caesium ozonide via an ion-exchange process.
Sodium ozonide (NaO3) is a red solid which is produced from caesium ozonide via an ion-exchange process.
Potassium ozonide (KO3) is a dark red solid which is produced when potassium is burned in ozone or exposed to air for years.
Rubidium ozonide (RbO3) is a dark red solid which is produced when rubidium is burned in ozone.
Caesium ozonide (CsO3) is a dark red solid which is produced when caesium is burned in ozone.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 33
Chapter 3: Alkali metal halide Alkali metal halides (also known as alkali halides) are the family of inorganic compounds with the chemical formula MX, where M is an alkali metal and X is a halogen. These compounds are the often commercially significant sources of these metals and halides. The best known of these compounds is sodium chloride, table salt.
Halite is the mineral form of sodium chloride.
Structure Most alkali metal halides crystallize with the face centered cubic lattices. In this structure both the metals and halides feature octahedral coordination geometry, in which each ion has a coordination number of six. Caesium chloride, bromide, and iodide crystallize in a bodycentered cubic lattice that accommodates coordination number of eight for the larger metal cation (and the anion also).
Ball-and-stick model of the coordination of Na and Cl in NaCl. Most alkali metal halides adopt this structure.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 34
Ball-and-stick model of the coordination of Cs and Cl in CsCl
Properties The alkali metal halides exist as colourless crystalline solids, although as finely ground powders appear white. They melt at high temperature, usually several hundred degrees to colorless liquids. Their high melting point reflects their high lattice energies. At still higher temperatures, these liquids evaporate to give gases composed of diatomic molecules. These compounds dissolve in polar solvents to give ionic solutions that contain highly solvated anions and cations. The table below provides links to each of the individual articles for these compounds. The numbers beside the compounds show the electronegativity difference between the elements based on the Pauling scale. The higher the number is, the more ionic the solid is. Alkali Metals Lithium Sodium
Potassium Rubidium Caesium
H Fluorine LiF (3.0) NaF (3.1) KF (3.2)
RbF (3.2) CsF (3.3)
a l Chlorine LiCl (2.0) NaCl (2.1) KCl (2.2)
RbCl (2.2) CsCl (2.3)
o g e
Bromine LiBr (1.8) NaBr (1.9) KBr (2.0)
RbBr (2.0) CsBr (2.1)
Iodine
RbI (1.7) CsI (1.8)
LiI (1.5) NaI (1.6) KI (1.7)
n s
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 35
Chapter 4: Melting point The melting point (or, rarely, liquefaction point) of a solid is the temperature at which it changes state from solid to liquid at atmospheric pressure. At the melting point the solid and liquid phase exist in equilibrium. The melting point of a substance depends (usually slightly) on pressure and is usually specified at standard pressure. When considered as the temperature of the reverse change from liquid to solid, it is referred to as the freezing point or crystallization point. Because of the ability of some substances to supercool, the freezing point is not considered as a characteristic property of a substance. When the "characteristic freezing point" of a substance is determined, in fact the actual methodology is almost always "the principle of observing the disappearance rather than the formation of ice", that is, the melting point. Examples
Melting points (in blue) and boiling points (in pink) of the first eight carboxylic acids (°C) For most substances, melting and freezing points are approximately equal. For example, the melting point and freezing point of mercury is 234.32 kelvin (−38.83 °C or −37.89 °F). However, certain substances possess differing solid-liquid transition temperatures. For example, agar melts at 85 °C (185 °F) and solidifies from 31 °C to 40 °C (89.6 °F to 104 °F); such direction dependence is known as hysteresis. The melting point of ice at 1 atmosphere of pressure is very close to 0 °C (32 °F, 273.15 K); this is also known as the ice point. In the presence of nucleating substances the freezing point of water is the same as the melting point, but in the absence of nucleators water can supercool to −42 °C (−43.6 °F, 231 K) before freezing. The chemical element with the highest melting point is tungsten, at 3687 K (3414 °C, 6177 °F) making it excellent for use as filaments in light bulbs. The often-cited carbon does not melt at ambient pressure but sublimes at about 4000 K; a liquid phase only exists above pressures of 10 MPa and estimated 4300–4700 K (see Carbon phase diagram). Tantalum hafnium carbide (Ta4HfC5) is a refractory compound with a very high melting point of 4488 K (4215 °C, 7619 °F). At the other end of the scale, helium does not freeze at all at normal pressure, even at temperatures very close to absolute zero; pressures over 20 times normal atmospheric pressure are necessary. Melting point measurements Main article: Melting point apparatus
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 36
Kofler bench with samples for calibration Many laboratory techniques exist for the determination of melting points. A Kofler bench is a metal strip with a temperature gradient (range from room temperature to 300 째C). Any substance can be placed on a section of the strip revealing its thermal behaviour at the temperature at that point. Differential scanning calorimetry gives information on melting point together with its enthalpy of fusion.
Automatic digital melting point meter A basic melting point apparatus for the analysis of crystalline solids consists of an oil bath with a transparent window (most basic design: a Thiele tube) and a simple magnifier. The several grains of a solid are placed in a thin glass tube and partially immersed in the oil bath. The oil bath is heated (and stirred) and with the aid of the magnifier (and external light source) melting of the individual crystals at a certain temperature can be observed. In large/small devices, the sample is placed in a heating block, and optical detection is automated. The measurement can also be made continuously with an operating process. For instance, oil refineries measure the freeze point of diesel fuel online, meaning that the sample is taken from the process and measured automatically. This allows for more frequent measurements as the sample does not have to be manually collected and taken to a remote laboratory.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 37
Thermodynamics
Pressure dependence of water melting point Not only is heat required to raise the temperature of the solid to the melting point, but the melting itself requires heat called the heat of fusion. From a thermodynamics point of view, at the melting point the change in Gibbs free energy (ΔG) of the material is zero, but the enthalpy (H) and the entropy (S) of the material are increasing (ΔH, ΔS > 0). Melting phenomenon happens when the Gibbs free energy of the liquid becomes lower than the solid for that material. At various pressures this happens at a specific temperature. It can also be shown that:
Here T, ΔS and ΔH are respectively the temperature at the melting point, change of entropy of melting and the change of enthalpy of melting. The melting point is sensitive to extremely large changes in pressure, but generally this sensitivity is orders of magnitude less than that for the boiling point, because the solid-liquid transition represents only a small change in volume. If, as observed in most cases, a substance is more dense in the solid than in the liquid state, the melting point will increase with increases in pressure. Otherwise the reverse behavior occurs. Notably, this is the case of water, as illustrated graphically to the right, but also of Si, Ge, Ga, Bi. With extremely large changes in pressure, substantial changes to the melting point are observed. For example, the melting point of silicon at ambient pressure (0.1 MPa) is 1415 °C, but at pressures in excess of 10 GPa it decreases to 1000 °C. Melting points are often used to characterize organic and inorganic compounds and to ascertain their purity. The melting point of a pure substance is always higher and has a smaller range than the melting point of an impure substance or, more generally, of mixtures. The higher the quantity of other components, the lower the melting point and the broader will be the melting point range, often referred to as the pasty range. The temperature at which melting begins for a mixture is known as the solidus while the temperature where melting is complete is called the liquidus. Eutectics are special types of mixtures that behave like single phases. They melt sharply at a constant temperature to form a liquid of the same composition. Alternatively, on cooling a liquid with the eutectic composition will solidify as uniformly dispersed, small (fine-grained) mixed crystals with the same composition. In contrast to crystalline solids, glasses do not possess a melting point; on heating they undergo a smooth glass transition into a viscous liquid. Upon further heating, they gradually soften, which can be characterized by certain softening points.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 38
Freezing-point depression Main article: Freezing-point depression The freezing point of a solvent is depressed when another compound is added, meaning that a solution has a lower freezing point than a pure solvent. This phenomenon is used in technical applications to avoid freezing, for instance by adding salt or ethylene glycol to water. Carnelley's Rule In organic chemistry Carnelley's Rule, established in 1882 by Thomas Carnelley, stated that high molecular symmetry is associated with high melting point. Carnelley based his rule on examination of 15,000 chemical compounds. For example for three structural isomers with molecular formula C5H12 the melting point increases in the series isopentane −160 °C (113 K) n-pentane −129.8 °C (143 K) and neopentane −16.4 °C (256.8 K). Likewise in xylenes and also dichlorobenzenes the melting point increases in the order meta, ortho and then para. Pyridine has a lower symmetry than benzene hence its lower melting point but the melting point again increases with diazine and triazines. Many cage-like compounds like adamantane and cubane with high symmetry have relatively high melting points. A high melting point results from a high heat of fusion, a low entropy of fusion, or a combination of both. In highly symmetrical molecules the crystal phase is densely packed with many efficient intermolecular interactions resulting in a higher enthalpy change on melting. Predicting the melting point of substances (Lindemann's criterion) An attempt to predict the bulk melting point of crystalline materials was first made in 1910 by Frederick Lindemann. The idea behind the theory was the observation that the average amplitude of thermal vibrations increases with increasing temperature. Melting initiates when the amplitude of vibration becomes large enough for adjacent atoms to partly occupy the same space. The Lindemann criterion states that melting is expected when the root mean square vibration amplitude exceeds a threshold value. Assuming that all atoms in a crystal vibrate with the same frequency ν, the average thermal energy can be estimated using the equipartition theorem as
where m is the atomic mass, ν is the frequency, u is the average vibration amplitude, k B is 2 the Boltzmann constant, and T is the absolute temperature. If the threshold value of u is 2 2 c a where c is the Lindemann constant and a is the atomic spacing, then the melting point is estimated as
Several other expressions for the estimated melting temperature can be obtained depending on the estimate of the average thermal energy. Another commonly used expression for the Lindemann criterion is
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 39
From the expression for the Debye frequency for ν, we have
where θD is the Debye temperature and h is the Planck constant. Values of c range from 0.15–0.3 for most materials. Open melting point data In February 2011Alfa Aesar released over 10,000 melting points of compounds from their catalog as open data. These data have been curated and are freely available for download. These data have been used to create a random forest model for melting point prediction which is now available as a free-to-use webservice. Highly curated and open melting point data are also available from Nature Precedings. See also
Liquidus temperature
List of elements by melting point
Melting points of the elements (data page)
Phases of matter
Triple point
Slip melting point
Solidus temperature
Bibliography
Haynes, William M., ed. (2011). CRC Handbook of Chemistry and Physics (92nd ed. ed.). CRC Press. ISBN 1439855110.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 40
Chapter 5: Boiling point
Boiling water The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid and the liquid changes into a vapor. A liquid in a vacuum has a lower boiling point than when that liquid is at atmospheric pressure. A liquid at high-pressure has a higher boiling point than when that liquid is at atmospheric pressure. In other words, the boiling point of a liquid varies depending upon the surrounding environmental pressure. For a given pressure, different liquids boil at different temperatures. The normal boiling point (also called the atmospheric boiling point or the atmospheric pressure boiling point) of a liquid is the special case in which the vapor pressure of the liquid equals the defined atmospheric pressure at sea level, 1 atmosphere. At that temperature, the vapor pressure of the liquid becomes sufficient to overcome atmospheric pressure and allow bubbles of vapor to form inside the bulk of the liquid. The standard boiling point is now (as of 1982) defined by IUPAC as the temperature at which boiling occurs under a pressure of 1 bar. The heat of vaporization is the energy required to transform a given quantity (a mol, kg, pound, etc.) of a substance from a liquid into a gas at a given pressure (often atmospheric pressure). Liquids may change to a vapor at temperatures below their boiling points through the process of evaporation. Evaporation is a surface phenomenon in which molecules located near the liquid's edge, not contained by enough liquid pressure on that side, escape into the surroundings as vapor. On the other hand, boiling is a process in which molecules anywhere in the liquid escape, resulting in the formation of vapor bubbles within the liquid.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 41
Saturation temperature and pressure A saturated liquid contains as much thermal energy as it can without boiling (or conversely a saturated vapor contains as little thermal energy as it can without condensing). Saturation temperature means boiling point. The saturation temperature is the temperature for a corresponding saturation pressure at which a liquid boils into its vapor phase. The liquid can be said to be saturated with thermal energy. Any addition of thermal energy results in a phase transition. If the pressure in a system remains constant (isobaric), a vapor at saturation temperature will begin to condense into its liquid phase as thermal energy (heat) is removed. Similarly, a liquid at saturation temperature and pressure will boil into its vapor phase as additional thermal energy is applied. The boiling point corresponds to the temperature at which the vapor pressure of the liquid equals the surrounding environmental pressure. Thus, the boiling point is dependent on the pressure. Usually, boiling points are published with respect to atmospheric pressure (101.325 kilopascals or 1 atm). At higher elevations, where the atmospheric pressure is much lower, the boiling point is also lower. The boiling point increases with increased pressure up to the critical point, where the gas and liquid properties become identical. The boiling point cannot be increased beyond the critical point. Likewise, the boiling point decreases with decreasing pressure until the triple point is reached. The boiling point cannot be reduced below the triple point. If the heat of vaporization and the vapor pressure of a liquid at a certain temperature is known, the normal boiling point can be calculated by using the Clausius-Clapeyron equation thus:
where: = the normal boiling point, K −1
−1
= the ideal gas constant, 8.314 J · K · mol
= is the vapor pressure at a given temperature, atm = the heat of vaporization of the liquid, J/mol
= the given temperature, K = the natural logarithm to the base e Saturation pressure is the pressure for a corresponding saturation temperature at which a liquid boils into its vapor phase. Saturation pressure and saturation temperature have a direct relationship: as saturation pressure is increased so is saturation temperature.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 42
If the temperature in a system remains constant (an isothermal system), vapor at saturation pressure and temperature will begin to condense into its liquid phase as the system pressure is increased. Similarly, a liquid at saturation pressure and temperature will tend to flash into its vapor phase as system pressure is decreased. The boiling point of water is 100 °C (212 °F) at standard pressure. On top of Mount Everest, at 8,848 m (29,029 ft) elevation, the pressure is about 252 Torr (33.597 kPa) and the boiling point of water is 71 °C (159.8 °F). The boiling point decreases 1 °C every 285 m of elevation, or 1 °F every 500 ft. There are two conventions regarding the standard boiling point of water: The normal boiling point is 99.97 degrees Celsius at a pressure of 1 atm (i.e., 101.325 kPa). Until 1982 this was also the standard boiling point of water, but the IUPAC now recommends a standard pressure of 1 bar (100 kPa). At this slightly reduced pressure, the standard boiling point of water is 99.61 degrees Celsius. Relation between the normal boiling point and the vapor pressure of liquids
A typical vapor pressure chart for various liquids The higher the vapor pressure of a liquid at a given temperature, the lower the normal boiling point (i.e., the boiling point at atmospheric pressure) of the liquid. The vapor pressure chart to the right has graphs of the vapor pressures versus temperatures for a variety of liquids. As can be seen in the chart, the liquids with the highest vapor pressures have the lowest normal boiling points.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 43
For example, at any given temperature, methyl chloride has the highest vapor pressure of any of the liquids in the chart. It also has the lowest normal boiling point (-24.2 °C), which is where the vapor pressure curve of methyl chloride (the blue line) intersects the horizontal pressure line of one atmosphere (atm) of absolute vapor pressure. Properties of the elements Further information: List of elements by boiling point The element with the lowest boiling point is helium. Both the boiling points of rhenium and tungsten exceed 5000 K at standard pressure; because it is difficult to measure extreme temperatures precisely without bias, both have been cited in the literature as having the higher boiling point. Boiling point as a reference property of a pure compound As can be seen from the above plot of the logarithm of the vapor pressure vs. the temperature for any given pure chemical compound, its normal boiling point can serve as an indication of that compound's overall volatility. A given pure compound has only one normal boiling point, if any, and a compound's normal boiling point and melting point can serve as characteristic physical properties for that compound, listed in reference books. The higher a compound's normal boiling point, the less volatile that compound is overall, and conversely, the lower a compound's normal boiling point, the more volatile that compound is overall. Some compounds decompose at higher temperatures before reaching their normal boiling point, or sometimes even their melting point. For a stable compound, the boiling point ranges from its triple point to its critical point, depending on the external pressure. Beyond its triple point, a compound's normal boiling point, if any, is higher than its melting point. Beyond the critical point, a compound's liquid and vapor phases merge into one phase, which may be called a superheated gas. At any given temperature, if a compound's normal boiling point is lower, then that compound will generally exist as a gas at atmospheric external pressure. If the compound's normal boiling point is higher, then that compound can exist as a liquid or solid at that given temperature at atmospheric external pressure, and will so exist in equilibrium with its vapor (if volatile) if its vapors are contained. If a compound's vapors are not contained, then some volatile compounds can eventually evaporate away in spite of their higher boiling points. In general, compounds with ionic bonds have high normal boiling points, if they do not decompose before reaching such high temperatures. Many metals have high boiling points, but not all. Very generally—with other factors being equal—in compounds with covalently bonded molecules, as the size of the molecule (or molecular mass) increases, the normal boiling point increases. When the molecular size becomes that of a macromolecule, polymer, or otherwise very large, the compound often decomposes at high temperature before the boiling point is reached. Another factor that affects the normal boiling point of a compound is the polarity of its molecules. As the polarity of a compound's molecules increases, its normal boiling point increases, other factors being equal. Closely related is the ability of a molecule to form hydrogen bonds (in the liquid state), which makes it harder for molecules to leave the liquid state and thus increases the normal boiling point of the compound. Simple carboxylic acids dimerize by forming hydrogen bonds between molecules. A minor factor affecting boiling points is the shape of a molecule. Making the shape of a molecule more compact tends to lower the normal boiling point slightly compared to an equivalent molecule with more surface area.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 44
Binary boiling point diagram of two hypothetical only weakly interacting components without an azeotrope Most volatile compounds (anywhere near ambient temperatures) go through an intermediate liquid phase while warming up from a solid phase to eventually transform to a vapor phase. By comparison to boiling, a sublimation is a physical transformation in which a solid turns directly into vapor, which happens in a few select cases such as with carbon dioxide at atmospheric pressure. For such compounds, a sublimation point is a temperature at which a solid turning directly into vapor has a vapor pressure equal to the external pressure. Impurities and mixtures In the preceding section, boiling points of pure compounds were covered. Vapor pressures and boiling points of substances can be affected by the presence of dissolved impurities (solutes) or other miscible compounds, the degree of effect depending on the concentration of the impurities or other compounds. The presence of non-volatile impurities such as salts or compounds of a volatility far lower than the main component compound decreases its mole fraction and the solution's volatility, and thus raises the normal boiling point in proportion to the concentration of the solutes. This effect is called boiling point elevation. As a common example, salt water boils at a higher temperature than pure water. In other mixtures of miscible compounds (components), there may be two or more components of varying volatility, each having its own pure component boiling point at any given pressure. The presence of other volatile components in a mixture affects the vapor pressures and thus boiling points and dew points of all the components in the mixture. The dew point is a temperature at which a vapor condenses into a liquid. Furthermore, at any given temperature, the composition of the vapor is different from the composition of the liquid in most such cases. In order to illustrate these effects between the volatile components in a mixture, a boiling point diagram is commonly used. Distillation is a process of boiling and [usually] condensation which takes advantage of these differences in composition between liquid and vapor phases.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 45
See also
Boiling points of the elements (data page)
Boiling-point elevation
Critical point (thermodynamics)
Ebulliometer
Joback method (Estimation of normal boiling points from molecular structure)
Subcooling
Superheating
Trouton's constant
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 46
Chapter 6: Density Density Common symbol(s): Ď SI unit:
3
kg/m
A graduated cylinder containing various coloured liquids with different densities.
The density, or more precisely, the volumetric mass density, of a substance is its mass per unit volume. The symbol most often used for density is Ď (the lower case Greek letter rho). Mathematically, density is defined as mass divided by volume:
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 47
where ρ is the density, m is the mass, and V is the volume. In some cases (for instance, in the United States oil and gas industry), density is loosely defined as its weight per unit volume, although this is scientifically inaccurate – this quantity is more specifically called specific weight. For a pure substance the density has the same numerical value as its mass concentration. Different materials usually have different densities, and density may be relevant to buoyancy, purity and packaging. Osmium and iridium are the densest known elements at standard conditions for temperature and pressure but certain chemical compounds may be denser. To simplify comparisons of density across different systems of units, it is sometimes replaced by the dimensionless quantity "specific gravity" or "relative density", i.e. the ratio of the density of the material to that of a standard material, usually water. Thus a specific gravity less than one means that the substance floats in water. The density of a material varies with temperature and pressure. This variation is typically small for solids and liquids but much greater for gases. Increasing the pressure on an object decreases the volume of the object and thus increases its density. Increasing the temperature of a substance (with a few exceptions) decreases its density by increasing its volume. In most materials, heating the bottom of a fluid results in convection of the heat from the bottom to the top, due to the decrease in the density of the heated fluid. This causes it to rise relative to more dense unheated material. The reciprocal of the density of a substance is occasionally called its specific volume, a term sometimes used in thermodynamics. Density is an intensive property in that increasing the amount of a substance does not increase its density; rather it increases its mass. History In a well-known but probably apocryphal tale, Archimedes was given the task of determining whether King Hiero's goldsmith was embezzling gold during the manufacture of a golden wreath dedicated to the gods and replacing it with another, cheaper alloy. Archimedes knew that the irregularly shaped wreath could be crushed into a cube whose volume could be calculated easily and compared with the mass; but the king did not approve of this. Baffled, Archimedes is said to have taken an immersion bath and observed from the rise of the water upon entering that he could calculate the volume of the gold wreath through the displacement of the water. Upon this discovery, he leapt from his bath and ran naked through the streets shouting, "Eureka! Eureka!" (Εύρηκα! Greek "I have found it"). As a result, the term "eureka" entered common parlance and is used today to indicate a moment of enlightenment. The story first appeared in written form in Vitruvius' books of architecture, two centuries after it supposedly took place. Some scholars have doubted the accuracy of this tale, saying among other things that the method would have required precise measurements that would have been difficult to make at the time. From the equation for density (ρ = m / V), mass density has units of mass divided by volume. As there are many units of mass and volume covering many different magnitudes there are a 3 large number of units for mass density in use. The SI unit of kilogram per cubic metre (kg/m ) 3 and the cgs unit of gram per cubic centimetre (g/cm ) are probably the most commonly used units for density. (The cubic centimeter can be alternately called a millilitre or a cc.) 3 3 1,000 kg/m equals one g/cm . In industry, other larger or smaller units of mass and or
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 48
volume are often more practical and US customary units may be used. See below for a list of some of the most common units of density. Measurement of density
Homogeneous materials The density at all points of a homogeneous object equals its total mass divided by its total volume. The mass is normally measured with a scale or balance; the volume may be measured directly (from the geometry of the object) or by the displacement of a fluid. To determine the density of a liquid or a gas, a hydrometer or dasymeter may be used, respectively. Similarly, hydrostatic weighing uses the displacement of water due to a submerged object to determine the density of the object. Inhomogeneous materials If the body is not homogeneous, then its density varies between different regions of the object. In that case the density around any given location is determined by calculating the density of a small volume around that location. In the limit of an infinitesimal volume the density of an inhomogeneous object at a point becomes: Ď (r) = dm/dV, where dV is an elementary volume at position r. The mass of the body then can be expressed as
Non-compact materials In practice, bulk materials such as sugar, sand, or snow contain voids. Many materials exist in nature as flakes, pellets, or granules. Voids are regions which contain something other than the considered material. Commonly the void is air, but it could also be vacuum, liquid, solid, or a different gas or gaseous mixture. The bulk volume of a material—inclusive of the void fraction—is often obtained by a simple measurement (e.g. with a calibrated measuring cup) or geometrically from known dimensions. Mass divided by bulk volume determines bulk density. This is not the same thing as volumetric mass density. To determine volumetric mass density, one must first discount the volume of the void fraction. Sometimes this can be determined by geometrical reasoning. For the close-packing of equal spheres the non-void fraction can be at most about 74%. It can also be determined empirically. Some bulk materials, however, such as sand, have a variable void fraction which depends on how the material is agitated or poured. It might be loose or compact, with more or less air space depending on handling. In practice, the void fraction is not necessarily air, or even gaseous. In the case of sand, it could be water, which can be advantageous for measurement as the void fraction for sand
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 49
saturated in water—once any air bubbles are thoroughly driven out—is potentially more consistent than dry sand measured with an air void. In the case of non-compact materials, one must also take care in determining the mass of the material sample. If the material is under pressure (commonly ambient air pressure at the earth's surface) the determination of mass from a measured sample weight might need to account for buoyancy effects due to the density of the void constituent, depending on how the measurement was conducted. In the case of dry sand, sand is so much denser than air that the buoyancy effect is commonly neglected (less than one part in one thousand). Mass change upon displacing one void material with another while maintaining constant volume can be used to estimate the void fraction, if the difference in density of the two void materials is reliably known. Changes of density Main articles: Compressibility and Thermal expansivity In general, density can be changed by changing either the pressure or the temperature. Increasing the pressure always increases the density of a material. Increasing the temperature generally decreases the density, but there are notable exceptions to this generalization. For example, the density of water increases between its melting point at 0 °C and 4 °C; similar behavior is observed in silicon at low temperatures. The effect of pressure and temperature on the densities of liquids and solids is small. The −6 −1 compressibility for a typical liquid or solid is 10 bar (1 bar = 0.1 MPa) and a typical −5 −1 thermal expansivity is 10 K . This roughly translates into needing around ten thousand times atmospheric pressure to reduce the volume of a substance by one percent. (Although the pressures needed may be around a thousand times smaller for sandy soil and some clays.) A one percent expansion of volume typically requires a temperature increase on the order of thousands of degrees Celsius. In contrast, the density of gases is strongly affected by pressure. The density of an ideal gas is
where M is the molar mass, P is the pressure, R is the universal gas constant, and T is the absolute temperature. This means that the density of an ideal gas can be doubled by doubling the pressure, or by halving the absolute temperature. In the case of volumic thermal expansion at constant pressure and small intervals of temperature the temperature dependence of density is :
where is the density at a reference temperature, the material at temperatures close to .
is the thermal expansion coefficient of
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 50
Density of solutions The density of a solution is the sum of mass (massic) concentrations of the components of that solution. Mass (massic) concentration of each given component Ď i in a solution sums to density of the solution.
Expressed as a function of the densities of pure components of the mixture and their volume participation, it reads:
provided that there is no interaction between the components. Densities
Water See also: Water density Density of water at 1 atm pressure: 3
Temp (°C)
Density (kg/m )
100
958.4
80
971.8
60
983.2
40
992.2
30
995.6502
25
997.0479
22
997.7735
20
998.2071
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 51
15
999.1026
10
999.7026
4
999.9720
0
999.8395
−10
998.117
−20
993.547
−30
983.854
The values below 0 °C refer to supercooled water.
Air Main article: Density of air
Density vs. temperature Density of air at 1 atm pressure:
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 52
3
T (°C) ρ (kg/m ) −25
1.423
−20
1.395
−15
1.368
−10
1.342
−5
1.316
0
1.293
5
1.269
10
1.247
15
1.225
20
1.204
25
1.184
30
1.164
35
1.146
Various materials Further information: Orders of magnitude (density) Unless otherwise noted, all densities given are at standard conditions for temperature and pressure, that is, 273.15 K (0.00 °C) and 100 kPa (0.987 atm). 3
Material
ρ (kg/m ) Notes
Helium
0.179
Aerographite
0.2
*
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 53
Metallic microlattice
0.9
*
Aerogel
1.0
*
Air
1.2
At sea level
Tungsten hexafluoride 12.4
One of the heaviest known gases under standard conditions
Liquid hydrogen
70
At ~ -255 째C
Styrofoam
75
Approx.
Cork
240
Approx.
Lithium
535
Wood
700
Potassium
860
Sodium
970
Ice
916.7
Water (fresh)
1,000
Water (salt)
1,030
Plastics
1,175
Tetrachloroethene
1,622
Magnesium
1,740
Beryllium
1,850
Glycerol
1,261
Silicon
2,330
Aluminium
2,700
Seasoned, typical
At temperature < 0 째C
Approx.; for polypropylene and PETE/PVC
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 54
Diiodomethane
3,325
Diamond
3,500
Titanium
4,540
Selenium
4,800
Vanadium
6,100
Antimony
6,690
Zinc
7,000
Chromium
7,200
Tin
7,310
Manganese
7,325
Iron
7,870
Niobium
8,570
Cadmium
8,650
Cobalt
8,900
Nickel
8,900
Copper
8,940
Bismuth
9,750
Molybdenum
10,220
Silver
10,500
Lead
11,340
Thorium
11,700
liquid at room temperature
Approx.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 55
Rhodium
12,410
Mercury
13,546
Tantalum
16,600
Uranium
18,800
Tungsten
19,300
Gold
19,320
Plutonium
19,840
Platinum
21,450
Iridium
22,420
Osmium
22,570
*Air excluded when calculating density Others 3
Entity
ρ (kg/m )
Interstellar medium
1×10
Assuming 90% H, 10% He; variable T
The Earth
5,515
Mean density.
−19
The inner core of the Earth 13,000 The core of the Sun
Notes
Approx., as listed in Earth.
33,000–160,000 Approx. 5
Super-massive black hole 9×10
Density of a 4.5-million-solar-mass black hole Event horizon radius is 13.5 million km. 9
Approx.
17
Does not depend strongly on size of nucleus
White dwarf star
2.1×10
Atomic nuclei
2.3×10
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 56
18
Neutron star
1×10
Stellar-mass black hole
1×10
18
Density
of
a
4-solar-mass
black
hole
Event horizon radius is 12 km.
Common units The SI unit for density is:
3
kilograms per cubic meter (kg/m )
Litres and metric tons are not part of the SI, but are acceptable for use with it, leading to the following units:
kilograms per liter (kg/L)
grams per milliliter (g/mL)
metric tons per cubic meter (t/m )
3
Densities using the following metric units all have exactly the same numerical value, one 3 3 thousandth of the value in (kg/m ). Liquid water has a density of about 1 kg/dm , making any of these SI units numerically convenient to use as most solids and liquids have densities 3 between 0.1 and 20 kg/dm .
kilograms per cubic decimetre (kg/dm )
grams per cubic centimetre (g/cm )
3
3
o
3
1 gram/cm = 1000 kg/m
3
3
megagrams (metric tons) per cubic metre (Mg/m )
In US customary units density can be stated in:
Avoirdupois ounces per cubic inch (oz/cu in)
Avoirdupois pounds per cubic inch (lb/cu in)
pounds per cubic foot (lb/cu ft)
pounds per cubic yard (lb/cu yd)
pounds per US liquid gallon (lb/gal)
pounds per US bushel (lb/bu)
slugs per cubic foot
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 57
Imperial units differing from the above (as the Imperial gallon and bushel differ from the US units) in practice are rarely used, though found in older documents. The density of precious metals could conceivably be based on Troy ounces and pounds, a possible cause of confusion. See also
List of elements by density
Charge density
Buoyancy
Bulk density
Dord
Energy density
Lighter than air
Number density
Orthobaric density
Specific weight
Spice (oceanography)
Standard temperature and pressure
Orders of magnitude (density)
Density prediction by the Girolami method
External links
Video: Density Experiment with Oil and Alcohol
Video: Density Experiment with Whiskey and Water
Glass Density Calculation – Calculation of the density of glass at room temperature and of glass melts at 1000 – 1400°C
List of Elements of the Periodic Table – Sorted by Density
Calculation of saturated liquid densities for some components
Field density test
On-line calculator for densities and partial molar volumes of aqueous solutions of some common electrolytes and their mixtures, at temperatures up to 323.15 K.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 58
Water – Density and specific weight
Temperature dependence of the density of water – Conversions of density units
A delicious density experiment
Water density calculator Water density for a given salinity and temperature.
Liquid density calculator Select a liquid from the list and calculate density as a function of temperature.
Gas density calculator Calculate density of a gas for as a function of temperature and pressure.
Densities of various materials.
Determination of Density of Solid, instructions for performing classroom experiment.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 59
Chapter 7: Ununennium Ununennium 119Uue
Fr ↑ Uue ↓ (Uhp)
ununoctium ← ununennium → unbinilium
Ununennium in the periodic table General properties Name, symbol, number Pronunciation
ununennium, Uue, 119
i
/uːn.uːnˈɛniəm/
oon-oon-EN-ee-əm Element category
unknown
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 60
but probably an alkali metal Group, period, block
1 (alkali metals), 8, s
Standard atomic weight
[315] (predicted)
Electron configuration
[Uuo]
1
8s (predicted)
2, 8, 18, 32, 32, 18, 8, 1 (predicted) History Naming
IUPAC systematic element name Physical properties
Phase
unknown (could be solid or liquid)
Density (near r.t.)
3 (predicted) g·cm
−3
Melting point
273–303 K32–86 0–30 °C, , (predicted) °F
Boiling point
1166 630 °C, 903 K, (predicted) °F
Heat of fusion
2.01–2.05 (extrapolated)kJ·mol
−1
Atomic properties Oxidation states Ionization energies
1, 3 (predicted) 1st: 463.1 (predicted) kJ·mol
−1
−1
2nd: 1698.1 (predicted) kJ·mol Atomic radius Covalent radius
240 (predicted)pm 263–281 (extrapolated) pm Most stable isotopes
Main article: Isotopes of ununennium
iso
NA half-life DM DE (MeV) DP
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 61
294
Uue (predicted) syn ~1–10 μs α
290
Uus
295
Uue (predicted) syn 0.2 ms
α
291
Uus
296
Uue (predicted) syn 0.2 ms
α
292
Uus
v
t
e
Ununennium, also known as eka-francium or element 119, is the temporary name of a chemical element in the periodic table that has the temporary symbol Uue and has the atomic number 119. To date, attempted syntheses of this element have been unsuccessful. Since it is below the alkali metals it might have properties similar to those of francium or caesium and thus be extremely reactive with water and air (though relativistic effects might make it less reactive than francium and caesium). A predicted oxidation state is +1; however, unlike all the other alkali metals, it is also predicted to show the +3 oxidation state. Ununennium would be the first element in the eighth period of the periodic table. Attempts at synthesis The synthesis of ununennium was attempted in 1985 by bombarding a target of einsteinium254 with calcium-48 ions at the superHILAC accelerator at Berkeley, California:
No atoms were identified, leading to a limiting yield of 300 nb. 295
As of May 2012, plans are under way to attempt to synthesize the isotopes Uue and 296 Uue by bombarding a target of berkelium with titanium at the GSI Helmholtz Centre for Heavy Ion Research in Darmstadt, Germany:
Predicted decay characteristics The alpha-decay half-lives of 1700 nuclei with 100 ≤ Z ≤ 130 have been calculated in a quantum tunneling model with alpha-decay Q-values from different mass estimates. The 291–307 alpha-decay half-lives predicted for 119 are of the order of micro-seconds. The highest value of the alpha-decay half-life predicted in the quantum tunneling model with the mass estimates from a macroscopic-microscopic model is ~485 microseconds for the isotope 294 302 119. For 119 it is ~163 microseconds.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 62
Target-projectile combinations leading to Z=119 compound nuclei The below table contains various combinations of targets and projectiles which could be used to form compound nuclei with an atomic number of 119. Target Projectile CN 254
48
302
249
50
299
Es Bk
Ca Ti
Attempt result
Uue Failure to date Uue Planned reaction
Theoretical calculations on evaporation cross sections The below table contains various targets-projectile combinations for which calculations have provided estimates for cross section yields from various neutron evaporation channels. The channel with the highest expected yield is given. DNS = Di-nuclear system; σ = cross section Target Projectile CN 254
Es
48
Ca
302
Channel (product) σ max Model Ref
Uue 3n (
299
Uue)
0.5 pb DNS
Extrapolated chemical properties Ununennium is expected to behave normally for an alkali metal and exhibit a strong +1 oxidation state. However, the energetic properties of its valence electron would increase its first ionization energy, making it less reactive than expected and more like potassium than caesium chemically. This would also decrease the metallic and ionic radii of ununennium. Ununennium is also predicted to be the first alkali metal to display the +3 oxidation state, due to the ionization energy of the 7p3/2 electrons, which is predicted to be very low. See also
Extended periodic table
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 63
Chapter 8: Hydrogen Hydrogen 1H
↑ H ↓ Li
- ← hydrogen → helium
Hydrogen in the periodic table Appearance
colorless gas
Purple glow in its plasma state
Spectral lines of hydrogen General properties Name, symbol, number Pronunciation
Element category
hydrogen, H, 1
/ˈhaɪdrədʒən/ HY-drə-jən
diatomic nonmetal
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 64
Group, period, block
1, 1, s
Standard atomic weight
1.008(1)
Electron configuration
1s
1
1 History Discovery
Henry Cavendish(1766)
Named by
Antoine Lavoisier(1783) Physical properties
Color
colorless
Phase
gas
Density
(0
°C,
101.325
kPa)
0.08988 g/L Liquid density at m.p.
0.07 (0.0763 solid) g·cm
Liquid density at b.p.
0.07099 g·cm
−3
−3
Melting point
13.99 K-434.49 °F -259.16 °C, ,
Boiling point
-423.182 °F -252.879 °C, 20.271 K,
Triple point
13.8033 K, 7.041 kPa
Critical point
32.938 K, 1.2858 MPa
Heat of fusion
(H2) 0.117 kJ·mol
Heat of vaporization
(H2) 0.904 kJ·mol
Molar heat capacity
(H2) 28.836 J·mol ·K
−1
−1
−1
−1
Vapor pressure
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 65
P (Pa) 1 10 100 1 k 10 k 100 k at T (K)
15
20
Atomic properties Oxidation states
1,
-1
(amphoteric oxide) Electronegativity
2.20 (Pauling scale)
Ionization energies
1st: 1312.0 kJ·mol
Covalent radius
31±5 pm
Van der Waals radius
120 pm
−1
Miscellanea Crystal structure
hexagonal
Magnetic ordering Thermal conductivity Speed of sound
diamagnetic −1
−1
0.1805 W·m ·K
(gas, 27 °C) 1310 m·s
CAS registry number
−1
1333-74-0
Most stable isotopes
Main article: Isotopes of hydrogen
iso
NA
half-life DM DE (MeV) DP
1
H 99.985% H is stable with 0 neutrons
1
2
H 0.015%
2
H is stable with 1 neutron
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 66
3
H
trace
−
12.32 y β
3
0.01861 He
Hydrogen is a chemical element with chemical symbol H and atomic number 1. With an atomic weight of 1.00794 u, hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in its plasma state. The most common isotope of hydrogen, termed protium (name rarely used, 1
symbol H), has a single proton and zero neutrons. The universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless, odorless, tasteless, nontoxic, nonmetallic, highly combustible diatomic gas with the molecular formula H2. Since hydrogen readily forms covalent compounds with most non-metallic elements, most of the hydrogen on Earth exists in molecular forms such as in the form of water or organic compounds. Hydrogen plays a particularly important role in acid–base reactions. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) known as a +
hydride, or as a positively charged (i.e., cation) species denoted by the symbol H . The hydrogen cation is written as though composed of a bare proton, but in reality, hydrogen cations in ionic compounds are always more complex species than that would suggest. As the simplest atom known, the hydrogen atom has had considerable theoretical application. For example, the hydrogen atom is the only neutral atom with an analytic solution to the Schrödinger equation. Hydrogen gas was first artificially produced in the early 16th century, via the mixing of metals with acids. In 1766–81, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance, and that it produces water when burned, a property which later gave it its name: in Greek, hydrogen means "water-former". Industrial production is mainly from the steam reforming of natural gas, and less often from more energy-intensive hydrogen production methods like the electrolysis of water. Most hydrogen is employed near its production site, with the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production, mostly for the fertilizer market. Hydrogen is a concern in metallurgy as it can embrittle many metals, complicating the design of pipelines and storage tanks.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 67
Properties
Combustion
The Space Shuttle Main Engine burnt hydrogen with oxygen, producing a nearly invisible flame at full thrust. Hydrogen gas (dihydrogen or molecular hydrogen) is highly flammable and will burn in air at a very wide range of concentrations between 4% and 75% by volume. The enthalpy of combustion for hydrogen is −286 kJ/mol: 2 H2(g) + O2(g) → 2 H2O(l) + 572 kJ (286 kJ/mol) Hydrogen gas forms explosive mixtures with air if it is 4–74% concentrated and with chlorine if it is 5–95% concentrated. The mixtures may be ignited by spark, heat or sunlight. The hydrogen autoignition temperature, the temperature of spontaneous ignition in air, is 500 °C (932 °F). Pure hydrogen-oxygen flames emit ultraviolet light and with high oxygen mix are nearly invisible to the naked eye, as illustrated by the faint plume of the Space Shuttle Main Engine compared to the highly visible plume of a Space Shuttle Solid Rocket Booster. The detection of a burning hydrogen leak may require a flame detector; such leaks can be very dangerous. Hydrogen flames in other conditions are blue, resembling blue natural gas flames. The destruction of the Hindenburg airship was an infamous example of hydrogen combustion; the cause is debated, but the visible orange flames were the result of a rich mixture of hydrogen to oxygen combined with carbon compounds from the airship skin. H2 reacts with every oxidizing element. Hydrogen can react spontaneously and violently at room temperature with chlorine and fluorine to form the corresponding hydrogen halides, hydrogen chloride and hydrogen fluoride, which are also potentially dangerous acids.
Electron energy levels Main article: Hydrogen atom
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 68
Depiction of a hydrogen atom with size of central proton shown, and the atomic diameter shown as about twice the Bohr model radius (image not to scale). The ground state energy level of the electron in a hydrogen atom is â&#x2C6;&#x2019;13.6 eV, which is equivalent to an ultraviolet photon of roughly 92 nm wavelength. The energy levels of hydrogen can be calculated fairly accurately using the Bohr model of the atom, which conceptualizes the electron as "orbiting" the proton in analogy to the Earth's orbit of the Sun. However, the electromagnetic force attracts electrons and protons to one another, while planets and celestial objects are attracted to each other by gravity. Because of the discretization of angular momentum postulated in early quantum mechanics by Bohr, the electron in the Bohr model can only occupy certain allowed distances from the proton, and therefore only certain allowed energies. A more accurate description of the hydrogen atom comes from a purely quantum mechanical treatment that uses the SchrĂśdinger equation or the Feynman path integral formulation to calculate the probability density of the electron around the proton. The most complicated treatments allow for the small effects of special relativity and vacuum polarization. In the quantum mechanical treatment, the electron in a ground state hydrogen atom has no angular momentum at allâ&#x20AC;&#x201D; an illustration of how different the "planetary orbit" conception of electron motion differs from reality.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 69
Elemental molecular forms
First tracks observed in liquid hydrogen bubble chamber at the Bevatron There exist two different spin isomers of hydrogen diatomic molecules that differ by the relative spin of their nuclei. In the orthohydrogen form, the spins of the two protons are parallel and form a triplet state with a molecular spin quantum number of 1 (½+½); in the parahydrogen form the spins are antiparallel and form a singlet with a molecular spin quantum number of 0 (½–½). At standard temperature and pressure, hydrogen gas contains about 25% of the para form and 75% of the ortho form, also known as the "normal form". The equilibrium ratio of orthohydrogen to parahydrogen depends on temperature, but because the ortho form is an excited state and has a higher energy than the para form, it is unstable and cannot be purified. At very low temperatures, the equilibrium state is composed almost exclusively of the para form. The liquid and gas phase thermal properties of pure parahydrogen differ significantly from those of the normal form because of differences in rotational heat capacities, as discussed more fully in spin isomers of hydrogen. The ortho/para distinction also occurs in other hydrogen-containing molecules or functional groups, such as water and methylene, but is of little significance for their thermal properties. The uncatalyzed interconversion between para and ortho H 2 increases with increasing temperature; thus rapidly condensed H2 contains large quantities of the high-energy ortho form that converts to the para form very slowly. The ortho/para ratio in condensed H 2 is an important consideration in the preparation and storage of liquid hydrogen: the conversion from ortho to para is exothermic and produces enough heat to evaporate some of the hydrogen liquid, leading to loss of liquefied material. Catalysts for the ortho-para interconversion, such as ferric oxide, activated carbon, platinized asbestos, rare earth metals, uranium compounds, chromic oxide, or some nickel compounds, are used during hydrogen cooling.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 70
Phases
Compressed hydrogen
Liquid hydrogen
Slush hydrogen
Solid hydrogen
Metallic hydrogen
Compounds Further information: Hydrogen compounds
Covalent and organic compounds While H2 is not very reactive under standard conditions, it does form compounds with most elements. Hydrogen can form compounds with elements that are more electronegative, such as halogens (e.g., F, Cl, Br, I), or oxygen; in these compounds hydrogen takes on a partial positive charge. When bonded to fluorine, oxygen, or nitrogen, hydrogen can participate in a form of medium-strength noncovalent bonding called hydrogen bonding, which is critical to the stability of many biological molecules. Hydrogen also forms compounds with less electronegative elements, such as the metals and metalloids, in which it takes on a partial negative charge. These compounds are often known as hydrides. Hydrogen forms a vast array of compounds with carbon called the hydrocarbons, and an even vaster array with heteroatoms that, because of their general association with living things, are called organic compounds. The study of their properties is known as organic chemistry and their study in the context of living organisms is known as biochemistry. By some definitions, "organic" compounds are only required to contain carbon. However, most of them also contain hydrogen, and because it is the carbon-hydrogen bond which gives this class of compounds most of its particular chemical characteristics, carbon-hydrogen bonds are required in some definitions of the word "organic" in chemistry. Millions of hydrocarbons are known, and they are usually formed by complicated synthetic pathways, which seldom involve elementary hydrogen.
Hydrides Compounds of hydrogen are often called hydrides, a term that is used fairly loosely. The term −
"hydride" suggests that the H atom has acquired a negative or anionic character, denoted H ,
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 71
and is used when hydrogen forms a compound with a more electropositive element. The existence of the hydride anion, suggested by Gilbert N. Lewis in 1916 for group I and II saltlike hydrides, was demonstrated by Moers in 1920 by the electrolysis of molten lithium hydride (LiH), producing a stoichiometry quantity of hydrogen at the anode. For hydrides other than group I and II metals, the term is quite misleading, considering the low electronegativity 2,
which
of
is
hydrogen. polymeric.
An
exception
In
lithium
in
group
II
aluminium
hydrides
hydride,
is
BeH
the
AlHâ&#x2C6;&#x2019;
4 anion carries hydridic centers firmly attached to the Al(III). Although hydrides can be formed with almost all main-group elements, the number and combination of possible compounds varies widely; for example, there are over 100 binary borane hydrides known, but only one binary aluminium hydride. Binary indium hydride has not yet been identified, although larger complexes exist. In inorganic chemistry, hydrides can also serve as bridging ligands that link two metal centers in a coordination complex. This function is particularly common in group 13 elements, especially in boranes (boron hydrides) and aluminium complexes, as well as in clustered carboranes.
Protons and acids Further information: Acidâ&#x20AC;&#x201C;base reaction +
Oxidation of hydrogen removes its electron and gives H , which contains no electrons and a +
nucleus which is usually composed of one proton. That is why H is often called a proton. This species is central to discussion of acids. Under the Bronsted-Lowry theory, acids are proton donors, while bases are proton acceptors. +
A bare proton, H , cannot exist in solution or in ionic crystals, because of its unstoppable attraction to other atoms or molecules with electrons. Except at the high temperatures associated with plasmas, such protons cannot be removed from the electron clouds of atoms and molecules, and will remain attached to them. However, the term 'proton' is sometimes used loosely and metaphorically to refer to positively charged or cationic hydrogen attached +
to other species in this fashion, and as such is denoted "H " without any implication that any single protons exist freely as a species. To avoid the implication of the naked "solvated proton" in solution, acidic aqueous solutions are sometimes considered to contain a less unlikely fictitious species, termed the "hydronium +
ion"(H3O ). However, even in this case, such solvated hydrogen cations are more realistically conceived +
9O 4.
as
being
organized
into
clusters
that
form
species
closer
to
H
Other oxonium ions are found when water is in acidic solution with other solvents.
Although exotic on Earth, one of the most common ions in the universe is the H
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
+ 3
ion, known
Page 72
as protonated molecular hydrogen or the trihydrogen cation. Isotopes Main article: Isotopes of hydrogen
Hydrogen discharge (spectrum) tube
Deuterium discharge (spectrum) tube
Protium, the most common isotope of hydrogen, has one proton and one electron. Unique among all stable isotopes, it has no neutrons (see diproton for a discussion of why others do not exist). Hydrogen has three naturally occurring isotopes, denoted 1H, 2H and 3H. Other, highly unstable nuclei (4H to 7H) have been synthesized in the laboratory but not observed in nature. 1.
1
H is the most common hydrogen isotope with an abundance of more than 99.98%.
Because the nucleus of this isotope consists of only a single proton, it is given the descriptive but rarely used formal name protium. 2.
2
H, the other stable hydrogen isotope, is known as deuterium and contains one
proton and one neutron in its nucleus. Essentially all deuterium in the universe is thought to have been produced at the time of the Big Bang, and has endured since
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 73
that time. Deuterium is not radioactive, and does not represent a significant toxicity hazard. Water enriched in molecules that include deuterium instead of normal hydrogen is called heavy water. Deuterium and its compounds are used as a nonradioactive
label
in
chemical
experiments
and
in
solvents
for
1
H-NMR spectroscopy. Heavy water is used as a neutron moderator and coolant for nuclear reactors. Deuterium is also a potential fuel for commercial nuclear fusion. 3.
3
H is known as tritium and contains one proton and two neutrons in its nucleus. It is
radioactive, decaying into helium-3 through beta decay with a half-life of 12.32 years. It is so radioactive that it can be used in luminous paint, making it useful in such things as watches. The glass prevents the small amount of radiation from getting out. Small amounts of tritium occur naturally because of the interaction of cosmic rays with atmospheric gases; tritium has also been released during nuclear weapons tests. It is used in nuclear fusion reactions, as a tracer in isotope geochemistry, and specialized in self-powered lighting devices. Tritium has also been used in chemical and biological labeling experiments as a radiolabel. Hydrogen is the only element that has different names for its isotopes in common use today. During the early study of radioactivity, various heavy radioactive isotopes were given their own names, but such names are no longer used, except for deuterium and tritium. The 2
3
symbols D and T (instead of H and H) are sometimes used for deuterium and tritium, but the corresponding symbol for protium, P, is already in use for phosphorus and thus is not available for protium. In its nomenclatural guidelines, the International Union of Pure and 2
3
2
3
Applied Chemistry allows any of D, T, H, and H to be used, although H, and H are preferred. History
Discovery and use Main article: Timeline of hydrogen technologies In 1671, Robert Boyle discovered and described the reaction between iron filings and dilute acids, which results in the production of hydrogen gas. In 1766, Henry Cavendish was the first to recognize hydrogen gas as a discrete substance, by naming the gas from a metalacid reaction "flammable air". He speculated that "flammable air" was in fact identical to the hypothetical substance called "phlogiston" and further finding in 1781 that the gas produces water when burned. He is usually given credit for its discovery as an element. In 1783, Antoine Lavoisier gave the element the name hydrogen (from the Greek ὕδρω hydro meaning water and γενῆς genes meaning creator) when he and Laplace reproduced
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 74
Cavendish's finding that water is produced when hydrogen is burned.
Antoine-Laurent de Lavoisier Lavoisier produced hydrogen for his experiments on mass conservation by reacting a flux of steam with metallic iron through an incandescent iron tube heated in a fire. Anaerobic oxidation of iron by the protons of water at high temperature can be schematically represented by the set of following reactions: Fe +
H2O → FeO + H2
2 Fe + 3 H2O → Fe2O3 + 3 H2 3 Fe + 4 H2O → Fe3O4 + 4 H2 Many metals such as zirconium undergo a similar reaction with water leading to the production of hydrogen. Hydrogen was liquefied for the first time by James Dewar in 1898 by using regenerative cooling and his invention, the vacuum flask. He produced solid hydrogen the next year.Deuterium was discovered in December 1931 by Harold Urey, and tritium was prepared in 1934 by Ernest Rutherford, Mark Oliphant, and Paul Harteck.Heavy water, which consists of deuterium in the place of regular hydrogen, was discovered by Urey's group in 1932.François Isaac de Rivaz built the first de Rivaz engine, an internal combustion engine powered by a mixture of hydrogen and oxygen in 1806. Edward Daniel Clarke invented the hydrogen gas blowpipe in 1819. The Döbereiner's lamp and limelight were invented in 1823. The first hydrogen-filled balloon was invented by Jacques Charles in 1783. Hydrogen provided the lift for the first reliable form of air-travel following the 1852 invention of the first hydrogen-lifted airship by Henri Giffard. German count Ferdinand von Zeppelin promoted the
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 75
idea of rigid airships lifted by hydrogen that later were called Zeppelins; the first of which had its maiden flight in 1900. Regularly scheduled flights started in 1910 and by the outbreak of World War I in August 1914, they had carried 35,000 passengers without a serious incident. Hydrogen-lifted airships were used as observation platforms and bombers during the war. The first non-stop transatlantic crossing was made by the British airship R34 in 1919. Regular passenger service resumed in the 1920s and the discovery of helium reserves in the United States promised increased safety, but the U.S. government refused to sell the gas for this purpose. Therefore, H2 was used in the Hindenburg airship, which was destroyed in a midair fire over New Jersey on May 6, 1937. The incident was broadcast live on radio and filmed. Ignition of leaking hydrogen is widely assumed to be the cause, but later investigations pointed to the ignition of the aluminized fabric coating by static electricity. But the damage to hydrogen's reputation as a lifting gas was already done. In the same year the first hydrogen-cooled turbogenerator went into service with gaseous hydrogen as a coolant in the rotor and the stator in 1937 at Dayton, Ohio, by the Dayton Power & Light Co, because of the thermal conductivity of hydrogen gas this is the most common type in its field today. The nickel hydrogen battery was used for the first time in 1977 aboard the U.S. Navy's Navigation technology satellite-2 (NTS-2). For example, the ISS,Mars Odyssey and the Mars Global Surveyor are equipped with nickel-hydrogen batteries. In the dark part of its orbit, the Hubble Space Telescope is also powered by nickel-hydrogen batteries, which were finally replaced in May 2009, more than 19 years after launch, and 13 years over their design life.
Role in quantum theory
Hydrogen emission spectrum lines in the visible range. These are the four visible lines of the Balmer series Because of its relatively simple atomic structure, consisting only of a proton and an electron, the hydrogen atom, together with the spectrum of light produced from it or absorbed by it, has been central to the development of the theory of atomic structure. Furthermore, the corresponding simplicity of the hydrogen molecule and the corresponding cation H+ 2 allowed fuller understanding of the nature of the chemical bond, which followed shortly after the quantum mechanical treatment of the hydrogen atom had been developed in the
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 76
mid-1920s. One of the first quantum effects to be explicitly noticed (but not understood at the time) was a Maxwell observation involving hydrogen, half a century before full quantum mechanical theory arrived. Maxwell observed that the specific heat capacity of H2 unaccountably departs from that of a diatomic gas below room temperature and begins to increasingly resemble that of a monatomic gas at cryogenic temperatures. According to quantum theory, this behavior arises from the spacing of the (quantized) rotational energy levels, which are particularly wide-spaced in H2 because of its low mass. These widely spaced levels inhibit equal partition of heat energy into rotational motion in hydrogen at low temperatures. Diatomic gases composed of heavier atoms do not have such widely spaced levels and do not exhibit the same effect.
Natural occurrence
NGC 604, a giant region of ionized hydrogen in the Triangulum Galaxy Hydrogen, as atomic H, is the most abundant chemical element in the universe, making up 75% of normal matter by mass and over 90% by number of atoms (most of the mass of the universe, however, is not in the form of chemical-element type matter, but rather is postulated to occur as yet-undetected forms of mass such as dark matter and dark energy). This element is found in great abundance in stars and gas giant planets. Molecular clouds of H2 are associated with star formation. Hydrogen plays a vital role in powering stars through the proton-proton reaction and the CNO cycle nuclear fusion. Throughout the universe, hydrogen is mostly found in the atomic and plasma states whose properties are quite different from molecular hydrogen. As a plasma, hydrogen's electron and proton are not bound together, resulting in very high electrical conductivity and high emissivity (producing the light from the Sun and other stars). The charged particles are highly
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 77
influenced by magnetic and electric fields. For example, in the solar wind they interact with the Earth's magnetosphere giving rise to Birkeland currents and the aurora. Hydrogen is found in the neutral atomic state in the interstellar medium. The large amount of neutral hydrogen found in the damped Lyman-alpha systems is thought to dominate the cosmological baryonic density of the Universe up to redshift z=4. Under ordinary conditions on Earth, elemental hydrogen exists as the diatomic gas, H 2 (for data see table). However, hydrogen gas is very rare in the Earth's atmosphere (1 ppm by volume) because of its light weight, which enables it to escape from Earth's gravity more easily than heavier gases. However, hydrogen is the third most abundant element on the Earth's surface, mostly in the form of chemical compounds such as hydrocarbons and water. Hydrogen gas is produced by some bacteria and algae and is a natural component of flatus, as is methane, itself a hydrogen source of increasing importance. +
A molecular form called protonated molecular hydrogen (H 3) is found in the interstellar medium, where it is generated by ionization of molecular hydrogen from cosmic rays. This charged ion has also been observed in the upper atmosphere of the planet Jupiter. The ion is relatively stable in the environment of outer space due to the low temperature and density. H
+ 3
is one of the most abundant ions in the Universe, and it plays a notable role in the
chemistry of the interstellar medium. Neutral triatomic hydrogen H 3 can only exist in an +
excited form and is unstable. By contrast, the positive hydrogen molecular ion (H 2) is a rare molecule in the universe. Thermochemical There are more than 200 thermochemical cycles which can be used for water splitting, around a dozen of these cycles such as the iron oxide cycle, cerium(IV) oxide窶田erium(III) oxide cycle, zinc zinc-oxide cycle, sulfur-iodine cycle, copper-chlorine cycle and hybrid sulfur cycle are under research and in testing phase to produce hydrogen and oxygen from water and heat without using electricity. A number of laboratories (including in France, Germany, Greece, Japan, and the USA) are developing thermochemical methods to produce hydrogen from solar energy and water.
Formation in transformers From all the fault gases formed in power transformers, hydrogen is the most common and is generated under most fault conditions; thus, formation of hydrogen is an early indication of serious problems in the transformer's life cycle.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 78
Xylose In 2014 a low-temperature 50 째C (122 째F), atmospheric-pressure enzyme-driven process to convert xylose into hydrogen with nearly 100% of the theoretical yield was announced. The process employs 13 enzymes, including a novel polyphosphatexylulokinase (XK).
Applications
Coolant Main article: Hydrogen-cooled turbo generator Hydrogen is commonly used in power stations as a coolant in generators due to a number of favorable properties that are a direct result of its light diatomic molecules. These include low density, low viscosity, and the highest specific heat and thermal conductivity of all gases.
Energy carrier See also: Hydrogen economy and Hydrogen infrastructure Hydrogen is not an energy resource, except in the hypothetical context of commercial nuclear fusion power plants using deuterium or tritium, a technology presently far from development. The Sun's energy comes from nuclear fusion of hydrogen, but this process is difficult to achieve controllably on Earth. Elemental hydrogen from solar, biological, or electrical sources require more energy to make it than is obtained by burning it, so in these cases hydrogen functions as an energy carrier, like a battery. Hydrogen may be obtained from fossil sources (such as methane), but these sources are unsustainable. The energy density per unit volume of both liquid hydrogen and compressed hydrogen gas at any practicable pressure is significantly less than that of traditional fuel sources, although the energy density per unit fuel mass is higher. Nevertheless, elemental hydrogen has been widely discussed in the context of energy, as a possible future carrier of energy on an economy-wide scale. For example, CO2 sequestration followed by carbon capture and storage could be conducted at the point of H2 production from fossil fuels. Hydrogen used in transportation would burn relatively cleanly, with some NO x emissions, but without carbon emissions. However, the infrastructure costs associated with full conversion to a hydrogen economy would be substantial. Semiconductor industry Hydrogen is employed to saturate broken ("dangling") bonds of amorphous silicon and
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 79
amorphous carbon that helps stabilizing material properties. It is also a potential electron donor in various oxide materials, including ZnO,SnO 2, CdO, MgO,ZrO2, HfO2, La2O3, Y2O3, TiO2, SrTiO3, LaAlO3, SiO2, Al2O3, ZrSiO4, HfSiO4, and SrZrO3.
Biological reactions Further information: Biohydrogen and Biological hydrogen production (Algae) H2 is a product of some types of anaerobic metabolism and is produced by several microorganisms, usually via reactions catalyzed by iron- or nickel-containing enzymes called hydrogenases. These enzymes catalyze the reversible redox reaction between H2 and its component two protons and two electrons. Creation of hydrogen gas occurs in the transfer of reducing equivalents produced during pyruvate fermentation to water. Water splitting, in which water is decomposed into its component protons, electrons, and oxygen, occurs in the light reactions in all photosynthetic organisms. Some such organisms, including the alga Chlamydomonas reinhardtii and cyanobacteria, have evolved a second step in the dark reactions in which protons and electrons are reduced to form H2 gas by specialized hydrogenases in the chloroplast. Efforts have been undertaken to genetically modify cyanobacterial hydrogenases to efficiently synthesize H 2 gas even in the presence of oxygen. Efforts have also been undertaken with genetically modified alga in a bioreactor.
Safety and precautions Main article: Hydrogen safety Hydrogen poses a number of hazards to human safety, from potential detonations and fires when mixed with air to being an asphyxiant in its pure, oxygen-free form. In addition, liquid hydrogen is a cryogen and presents dangers (such as frostbite) associated with very cold liquids. Hydrogen dissolves in many metals, and, in addition to leaking out, may have adverse effects on them, such as hydrogen embrittlement, leading to cracks and explosions. Hydrogen gas leaking into external air may spontaneously ignite. Moreover, hydrogen fire, while being extremely hot, is almost invisible, and thus can lead to accidental burns. Even interpreting the hydrogen data (including safety data) is confounded by a number of phenomena. Many physical and chemical properties of hydrogen depend on the parahydrogen/orthohydrogen ratio (it often takes days or weeks at a given temperature to reach the equilibrium ratio, for which the data is usually given). Hydrogen detonation parameters, such as critical detonation pressure and temperature, strongly depend on the container geometry.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 80
See also 1. Antihydrogen 2. Fuel cell 3. Hydrogen cycle 4. Hydrogen ion 5. Oxyhydrogen
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 81
Chapter 9: Ammonium The ammonium cation is a positively charged polyatomic ion with the chemical formula +
NH4 . It is formed by the protonation of ammonia (NH3). Ammonium is also a general name for positively charged or protonated substituted amines and quaternary ammonium cations +
(NR4 ), where one or more hydrogen atoms are replaced by organic radical groups (indicated by R). Acid base properties The ammonium ion is generated when ammonia, a weak base, reacts with Brønsted acids (proton donors): +
+
H + NH3 → NH4
+
The acid dissociation constant (pKa) of NH4 is 9.25. The ammonium ion is mildly acidic, reacting with Brønsted bases to return to the uncharged ammonia molecule: +
−
NH4 + B → HB + NH3 Thus, treatment of concentrated solutions of ammonium salts with strong base gives ammonia. When ammonia is dissolved in water, a tiny amount of it converts to ammonium ions: +
+
H3O + NH3 H2O + NH4
The degree to which ammonia forms the ammonium ion depends on the pH of the solution. If the pH is low, the equilibrium shifts to the right: more ammonia molecules are converted into ammonium ions. If the pH is high (the concentration of hydrogen ions is low), the equilibrium shifts to the left: the hydroxide ion abstracts a proton from the ammonium ion, generating ammonia. Formation of ammonium compounds can also occur in the vapor phase; for example, when ammonia vapor comes in contact with hydrogen chloride vapor, a white cloud of ammonium chloride forms, which eventually settles out as a solid in a thin white layer on surfaces. The conversion of ammonium back to ammonia is easily accomplished by the addition of a strong base. Formation of ammonium Ammonium cation is found in a variety of salts such as ammonium carbonate, ammonium
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 82
chloride, and ammonium nitrate. Most simple ammonium salts are very soluble in water. An exception is ammonium hexachloroplatinate, the formation of which was once used as a test for ammonium. The ammonium salts of nitrate and especially perchlorate are highly explosive, in these cases ammonium is the reducing agent. In an unusual process, ammonium ions form an amalgam. Such species are prepared by the electrolysis of an ammonium solution using a mercury cathode. This amalgam eventually decomposes to release ammonia and hydrogen. Structure and bonding The lone electron pair on the nitrogen atom (N) in ammonia, represented as a pair of dots, +
forms the bond with a proton (H ). Thereafter, all four N-H bonds are equivalent, being polar covalent bonds. The ion is isoelectronic with methane and borohydride. In terms of size, the ammonium cation (rionic = 175 pm) resembles the caesium cation (rionic = 183 pm). Organic ammonium ions The hydrogen atoms in the ammonium ion can be substituted with an alkyl group or some other organic group to form a substituted ammonium ion (IUPAC nomenclature": aminium ion). Depending on the number of organic groups, the ammonium cation is called a primary, secondary, tertiary, or quaternary. With the exception of the quaternary ammonium cations, the organic ammonium cations are weak acids. An example of a reaction forming an ammonium ion is that between dimethylamine, (CH3)2NH,
and
an
acid,
to
give
the
dimethylaminium
cation,
(CH3)2NH+
Quaternary ammonium cations have four organic groups attached to the nitrogen atom. They lack a hydrogen atom bonded to the nitrogen atom. These cations, such as the tetra-nbutylammonium cation, are sometimes used to replace sodium or potassium ions to increase the solubility of the associated anion in organic solvents. Primary, secondary, and tertiary ammonium salts serve the same function, but are less lipophilic. They are also used as phase-transfer catalysts and surfactants. Biology Ammonium ions are a waste product of the metabolism of animals. In fish and aquatic invertebrates, it is excreted directly into the water. In mammals, sharks, and amphibians, it is converted in the urea cycle to urea, because urea is less toxic and can be stored more efficiently. In birds, reptiles, and terrestrial snails, metabolic ammonium is converted into uric acid, which is solid and can therefore be excreted with minimal water loss. Ammonium is an important source of nitrogen for many plant species, especially those growing on hypoxic soils. However, it is also toxic to most crop species and is rarely applied
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 83
as a sole nitrogen source. Ammonium metal The ammonium ion has very similar properties to the heavier alkali metals and is often considered a close relative. Ammonium is expected to behave as a metal (NH+ 4 ions in a sea of electrons) at very high pressures, such as inside gas giant planets such as Uranus and Neptune. See also
Ammonium transporter
f-ratio
Hydronium (H3O )
Iminium
Nitrification
Onium compounds
+
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 84
Chapter 10: Thallium Thallium 81Tl
In ↑ Tl ↓ Uut
mercury ← thallium → lead
Thallium in the periodic table Appearance
silvery white
General properties Name, symbol, number Pronunciation
thallium, Tl, 81 /ˈθæliəm/ THAL-ee-əm
Element category
poor metal
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 85
Group, period, block
13, 6, p
Standard atomic weight
204.38(1)
Electron configuration
[Xe]
4f
14
5d
10
6s
2
6p
1
2, 8, 18, 32, 18, 3 History Discovery
William Crookes (1861)
First isolation
Claude-Auguste Lamy (1862) Physical properties
Phase
solid
Density (near r.t.)
11.85 g·cm
Liquid density at m.p.
11.22 g·cm
−3
−3
Melting point
577 K579 °F 304 °C, ,
Boiling point
2683 °F 1473 °C, 1746 K,
Heat of fusion
4.14 kJ·mol
Heat of vaporization
165 kJ·mol
Molar heat capacity
26.32 J·mol ·K
−1
−1
−1
−1
Vapor pressure
P (Pa) 1
10 100 1 k 10 k 100 k
at T (K) 882 977 1097 1252 1461 1758
Atomic properties Oxidation states
3, 2, 1 (mildly basic oxide)
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 86
Electronegativity
1.62 (Pauling scale)
Ionization energies
1st: 589.4 kJ·mol
−1
2nd: 1971 kJ·mol 3rd: 2878 kJ·mol Atomic radius
−1
−1
170 pm
Covalent radius
145±7 pm
Van der Waals radius
196 pm Miscellanea
Crystal structure
Magnetic ordering Electrical resistivity Thermal conductivity Thermal expansion Speed of sound (thin rod) Young's modulus
hexagonal close-packed
diamagnetic (20 °C) 0.18 µΩ·m −1
−1
46.1 W·m ·K
−1
−1
(25 °C) 29.9 µm·m ·K (20 °C) 818 m·s
−1
8 GPa
Shear modulus
2.8 GPa
Bulk modulus
43 GPa
Poisson ratio
0.45
Mohs hardness
1.2
Brinell hardness
26.4 MPa
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 87
CAS registry number
7440-28-0
Most stable isotopes
Main article: Isotopes of thallium
iso
NA
half-life
DM
DE (MeV) 0.9108
199
Au
0.764
204
Pb
ε
0.347
204
(α)
0.1567
201
203
Tl
29.524%
-
(α)
204
Tl
syn
3.78 y
β
205
Tl
70.476%
-
−
DP
Hg Au
Decay modes in parentheses are predicted, but have not yet been observed
v t e
Thallium is a chemical element with symbol Tl and atomic number 81. This soft gray poor metal is not found free in nature. When isolated, it resembles tin, but discolors when exposed to air. Chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861, in residues of sulfuric acid production. Both used the newly developed method of flame spectroscopy, in which thallium produces a notable green spectral line. Thallium, from Greek θαλλός, thallos, meaning "a green shoot or twig," was named by Crookes. It was isolated by electrolysis a year later, by Lamy. Thallium tends to oxidize to the +3 and +1 oxidation states as ionic salts. The +3 state resembles that of the other elements in thallium's group (boron, aluminum, gallium, indium). However, the +1 state, which is far more prominent in thallium than the elements above it, recalls the chemistry of alkali metals, and thallium(I) ions are found geologically mostly in potassium-based ores, and (when ingested) are handled in many ways like potassium ions +
(K ) by ion pumps in living cells. Commercially, however, thallium is produced not from potassium ores, but as a byproduct from refining of heavy metal sulfide ores. Approximately 60–70% of thallium production is used in the electronics industry, and the remainder is used in the pharmaceutical industry and in glass manufacturing. It is also used in infrared detectors. The radioisotope thallium-
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 88
201 (as the soluble chloride TlCl) is used in small, nontoxic amounts as an agent in a nuclear medicine scan, during one type of nuclear cardiac stress test. Soluble thallium salts (many of which are nearly tasteless) are highly toxic in quantity, and were historically used in rat poisons and insecticides. Use of these compounds has been restricted or banned in many countries, because of their nonselective toxicity. Notably, thallium poisoning results in hair loss. Because of its historic popularity as a murder weapon, thallium has gained notoriety as "the poisoner's poison" and "inheritance powder" (alongside arsenic).
Characteristics Thallium is extremely soft, malleable and sectile enough to be cut with a knife at room temperature. It has a metallic luster that, when exposed to air, quickly tarnishes to a bluishgray tinge, resembling lead. It may be preserved by immersion in oil. A heavy layer of oxide builds up on thallium if left in air. In the presence of water, thallium hydroxide is formed. Sulfuric and nitric acid dissolve thallium rapidly to make the sulfate and nitrate salts, while hydrochloric acid forms an insoluble thallium(I) chloride layer. Its standard electrode potential is â&#x2C6;&#x2019;0.34, slightly higher than the potential for iron (at â&#x2C6;&#x2019;0.44).
Isotopes Main article: Isotopes of thallium Thallium has 25 isotopes which have atomic masses that range from 184 to 210. 205
Tl are the only stable isotopes, and
204
203
Tl and
Tl is the most stable radioisotope, with a half-life of
3.78 years. 202
Tl (half-life 12.23 days) can be made in a cyclotron, while
204
Tl is made by the neutron
activation of stable thallium in a nuclear reactor. 201
Tl (half-life 73 hrs), decays by electron capture, emitting Hg X-rays (~70â&#x20AC;&#x201C;80 keV), and
photons of 135 and 167 keV in 10% total abundance; therefore it has good imaging characteristics without excessive patient radiation dose. It is the most popular isotope used for thallium nuclear cardiac stress tests. 208
Tl (half-life 3.05 minutes) is generated in the naturally-occurring thorium decay chain. Its
prominent 2615 keV gamma ray is the dominant high-energy feature observed in natural background radiation.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 89
Chemistry See also category: Thallium compounds The two main oxidation states of thallium are +1 and +3. In the oxidation state +1 most compounds closely resemble the corresponding potassium or silver compounds (the ionic radius of thallium(I) is 1.47 Å while that of potassium is 1.33 Å and that of silver is [citation needed]
1.26 Å),
which was the reason why thallium was sometimes considered to be an
alkali metal in Europe (but not in England) in the years immediately following its discovery. For example, the water-soluble and very basic thallium(I) hydroxide reacts with carbon dioxide forming water-soluble thallium carbonate. This carbonate is the only water soluble heavy metal carbonate.
[citation needed]
The similarity with silver compounds is observed with the
halide, oxide, and sulfide compounds. Thallium(I) bromide is a photosensitive yellow compound very similar to the silver bromide, while the black thallium(I) oxide and thallium(I) sulfide are very similar to the silver oxide and silver sulfide.
[citation needed]
The compounds with oxidation state +3 resemble the corresponding aluminium(III) compounds. They are moderately strong oxidizing agents, as illustrated by the reduction potential of +0.72 volts for Tl
3+
–
+ 3 e → Tl(s). The thallium(III) oxide is a black solid which
decomposes above 800 °C, forming the thallium(I) oxide and oxygen.
History Thallium (Greek θαλλός, thallos, meaning "a green shoot or twig") was discovered by flame spectroscopy in 1861. The name comes from thallium's bright green spectral emission lines. After the publication of the improved method of flame spectroscopy by Robert Bunsen and Gustav Kirchhoff and the discovery of caesium and rubidium in the years 1859 to 1860, flame spectroscopy became an approved method to determine the composition of minerals and chemical products. William Crookes and Claude-Auguste Lamy both started to use the new method. William Crookes used it to make spectroscopic determinations for tellurium on selenium compounds deposited in the lead chamber of a sulfuric acid production plant near Tilkerode in the Harz mountains. He had obtained the samples for his research on selenium cyanide from August Hofmann years earlier. By 1862, Crookes was able to isolate small quantities of the new element and determine the properties of a few compounds. ClaudeAuguste Lamy used a spectrometer that was similar to Crookes' to determine the composition of a selenium-containing substance which was deposited during the production of sulfuric acid from pyrite. He also noticed the new green line in the spectra and concluded that a new element was present. Lamy had received this material from the sulfuric acid plant of his friend Fréd Kuhlmann and this by-product was available in large quantities. Lamy
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 90
started to isolate the new element from that source. The fact that Lamy was able to work ample quantities of thallium enabled him to determine the properties of several compounds and in addition he prepared a small ingot of metallic thallium which he prepared by remelting thallium he had obtained by electrolysis of thallium salts. As both scientists discovered thallium independently and a large part of the work, especially the isolation of the metallic thallium was done by Lamy, Crookes tried to secure his priority on the work. Lamy was awarded a medal at the International Exhibition in London 1862: For the discovery of a new and abundant source of thallium and after heavy protest Crookes also received a medal: thallium, for the discovery of the new element. The controversy between both scientists continued through 1862 and 1863. Most of the discussion ended after Crookes was elected Fellow of the Royal Society in June 1863. The dominant use of thallium was the use as poison for rodents. After several accidents the use as poison was banned in the United States by the Presidential Executive Order 11643 in February 1972. In the subsequent years several other countries also banned the use.
Occurrence and production Although thallium is a modestly abundant element in the Earth's crust, with a concentration estimated to be about 0.7 mg/kg, mostly in association with potassium-based minerals in clays, soils, and granites, thallium is not generally economically recoverable from these sources. The major source of thallium for practical purposes is the trace amount that is found in copper, lead, zinc, and other heavy-metal-sulfide ores.
Crystals of hutchinsonite (TlPbAs5S9) Thallium is found in the minerals crookesite TlCu7Se4, hutchinsonite TlPbAs5S9, and lorandite TlAsS2. Thallium also occurs as a trace element in iron pyrite, and thallium is extracted as a by-product of roasting this mineral for the production of sulfuric acid. Thallium can also be obtained from the smelting of lead and zinc ores. Manganese nodules found on the ocean floor also contain some thallium, but the collection of these nodules has
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 91
been and continues to be prohibitively expensive. There is also the potential for damaging the environment of the oceans. In addition, several other thallium minerals, containing 16% to 60% thallium, occur in nature as complexes of sulfides or selenides that primarily contain antimony, arsenic, copper, lead, and/or silver. However, these minerals are rare, and they have had no commercial importance as sources of thallium. The Allchar deposit in southern Macedonia was the only area where thallium was ever actively mined. This deposit still contains a loosely estimated 500 tonnes of thallium, and it is a source for several rare thallium minerals, for example lorandite. The United States Geological Survey (USGS) estimates that the annual worldwide production of thallium is about 10 metric tonnes as a by-product from the smelting of copper, zinc, and lead ores. Thallium is either extracted from the dusts from the smelter flues or from residues such as slag that are collected at the end of the smelting process. The raw materials used for thallium production contain large amounts of other materials and therefore a purification is the first step. The thallium is leached either by the use of a base or sulfuric acid from the material. The thallium is several times precipitated from the solution and to remove further impurities. At the end it is converted to thallium sulfate and the thallium is extracted by electrolysis on platinum or stainless steel plates. The production of thallium decreased by about 33% in the period from 1995 to 2009 â&#x20AC;&#x201C; from about 15 metric tonnes to about 10 tonnes. Since there are several small deposits or ores with relatively high thallium content, it would be possible to increase the production of it if a new application, such as a hypothetical thallium-containing high-temperature superconductor, becomes practical for widespread use outside of the laboratory.
Applications
Historic uses The odorless and tasteless thallium sulfate was once widely used as rat poison and ant killer. Since 1972 this use has been prohibited in the United States due to safety concerns. Many other countries followed this example in the following years. Thallium salts were used in the treatment of ringworm, other skin infections and to reduce the night sweating of tuberculosis patients. However this use has been limited due to their narrow therapeutic index, and the development of more advanced medicines for these conditions.
Optics Thallium(I) bromide and thallium(I) iodide crystals have been used as infrared optical materials, because they are harder than other common infrared optics, and because they
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 92
have transmission at significantly longer wavelengths. The trade name KRS-5 refers to this material.Thallium(I) oxide has been used to manufacture glasses that have a high index of refraction. Combined with sulfur or selenium and arsenic, thallium has been used in the production of high-density glasses that have low melting points in the range of 125 and 150 째C. These glasses have room temperature properties that are similar to ordinary glasses and are durable, insoluble in water and have unique refractive indices.
Electronics
Corroded thallium rod Thallium(I) sulfide's electrical conductivity changes with exposure to infrared light therefore making this compound useful in photoresistors. Thallium selenide has been used in a bolometer for infrared detection. Doping selenium semiconductors with thallium improves their performance, and therefore it is used in trace amounts in selenium rectifiers. Another application of thallium doping is the sodium iodide crystals in gamma radiation detection devices. In these, the sodium iodide crystals are doped with a small amount of thallium to improve their efficiency as scintillation generators. Some of the electrodes in dissolved oxygen analyzers contain thallium.
High-temperature superconductivity Research activity with thallium is ongoing to develop high-temperature superconducting materials for such applications as magnetic resonance imaging, storage of magnetic energy, magnetic propulsion, and electric power generation and transmission. The research in applications started after the discovery of the first thallium barium calcium copper oxide superconductor in 1988. Thallium cuprate superconductors have been discovered that have transition temperatures above 120K. Some mercury doped thallium cuprate superconductors have transition temperatures above 130 K at ambient pressure,nearly as high as the world record holding mercury cuprates.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 93
Medical Before the widespread application of technetium-99m in nuclear medicine, the radioactive isotope thallium-201, with a half-life of 73 hours, was the main substance for nuclear cardiography. The nuclide is still used for stress tests for risk stratification in patients with coronary artery disease (CAD). This isotope of thallium can be generated using a transportable generator which is similar to the technetium-99m generator. The generator contains lead-201 (half-life 9.33 hours) which decays by electron capture to the thallium-201. The lead-201 can be produced in a cyclotron by the bombardment of thallium with protons or deuterons by the (p,3n) and (d,4n) reactions.
Thallium stress test A thallium stress test is a form of scintigraphy, where the amount of thallium in tissues +
+
correlates with tissue blood supply. Viable cardiac cells have normal Na /K ion exchange +
+
pumps. The Tl cation binds the K pumps and is transported into the cells. Exercise or dipyridamole induces widening (vasodilation) of normal coronary arteries. This produces coronary steal from areas where arteries are maximally dilated. Areas of infarct or ischemic tissue will remain "cold". Pre- and post-stress thallium may indicate areas which will benefit from myocardial revascularization. Redistribution indicates the existence of coronary steal and the presence of ischemic coronary artery disease.
Other uses A mercury-thallium alloy, which forms a eutectic at 8.5% thallium, is reported to freeze at −60 °C, some 20 °C below the freezing point of mercury. This alloy is used in thermometers and low-temperature switches. In organic synthesis, thallium(III) salts, as thallium trinitrate or triacetate, are useful reagents performing different transformations in aromatics, ketones, olefins, among others. Thallium is a constituent of the alloy in the anode plates in magnesium seawater batteries. Soluble thallium salts are added to gold plating baths to increase the speed of plating and to reduce grain size within the gold layer. The saturated solution of equal parts of thallium(I) formate (Tl(CHO 2)) and thallium(I) malonate (Tl(C3H3O4)) in water is known as Clerici solution. It is a mobile odorless liquid whose color changes from yellowish to clear upon reducing the concentration of the thallium 3
salts. With the density of 4.25 g/cm at 20 °C, Clerici solution is one of the heaviest aqueous solutions known. It was used in the 20th century for measuring density of minerals by the flotation method, but the use is discontinued due to the high toxicity and corrosiveness of the solution.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 94
Thallium iodide is used as an additive to metal halide lamps, often together with one-two halides of other metals. It allows to optimize the lamp temperature and color rendering, and shift the spectral output to the green region, which is useful for underwater lighting.
Toxicity Main article: Thallium poisoning Thallium and its compounds are extremely toxic, and should be handled with great care. There are numerous recorded cases of fatal thallium poisoning. Contact with skin is dangerous, and adequate ventilation should be provided when melting this metal. Thallium(I) compounds have a high aqueous solubility and are readily absorbed through the skin. Exposure by inhalation should not exceed 0.1 mg per cubic metre in an 8-hour time-weighted average (40-hour work week). Thallium will readily absorb through the skin and care should be taken to avoid this route of exposure as cutaneous absorption can exceed the absorbed dose received by inhalation at the PEL. Thallium is a suspected human carcinogen. For a long time thallium compounds were easily available as rat poison. This fact and that it is water soluble and nearly tasteless led to frequent intoxication caused by accident or criminal intent.
Treatment and internal decontamination One of the main methods of removing thallium (both radioactive and normal) from humans is to use Prussian blue, a material which absorbs thallium. Up to 20 g per day of Prussian blue is fed by mouth to the person, and it passes through their digestive system and comes out in the stool. Hemodialysis and hemoperfusion are also used to remove thallium from the blood serum. At later stage of the treatment additional potassium is used to mobilize thallium from the tissue.
Thallium pollution According to the United States Environmental Protection Agency (EPA), man-made sources of thallium pollution include gaseous emission of cement factories, coal burning power plants, and metal sewers. The main source of elevated thallium concentrations in water is the leaching of thallium from ore processing operations.
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 95
See also
External links 4. Thallium at The Periodic Table of Videos (University of Nottingham) 5. Toxicity, thallium 6. NLM hazardous substances databank – Thallium, elemental 7. ATSDR – ToxFAQs 8. CDC - NIOSH Pocket Guide to Chemical Hazards
Article Sources and Contributors
Alkali metal Source: https://en.wikipedia.org/w/index.php?oldid=592582391 Contributors: 09phippsj, 1297, 1exec1, 64.26.98.xxx, 90 Auto, AMK152, AOC25, Abshirdheere, Academic Challenger, Acereiner, Achim1999, Achowat, Acroterion, Addshore, Aeblic, Ahoerstemeier, Alansohn, Alchemist-hp, Alex43223, Alexander336, Allmightyduck, Andre Engels, AndrewWTaylor, Andy M. Wang, Angela, Anonymous Paul, Avoided, AxelBoldt, Ayeroxor, Ayla, Badseed, Badwolftv, Bagatelle, Bart133, Basement12, Benbest, Benjah-bmm27, Betacommand, Biker Biker, Blueberryfart, Bomac, Bongwarrior, Borek, Braincricket, Brockert, Brumski, Bryanw03, Bulwersator, BunnyNotCorcoran, CSumit, CWii, Camp3rstrik3r, Candlemb, CardinalDan, Casliber, Cbrown1023, Charlie999, Cheeseman557, Chemicalinterest, Chester Markel, Chris Dybala, Chris the speller, Chris857, ChrisGualtieri, Christian75, Cimex, Cinderblock63, Clorox, Coffee, Colbuckshot, Conversion script, Countmippipopolous, Cpl Syx, Cruccone, DARTH SIDIOUS 2, DMacks, DO11.10, DanDao, David Cat, Dawn Bard, Dbc334, Dcljr, DePiep, Deagle AP, Derek Ross, DexDor, Dittaeva, DocPhilBrown, Domesticenginerd, Double sharp, Doulos Christos, Dozzabird, Drahgo, Drphilharmonic, Dungodung, Dvratnam, EL Willy, Eddideigel, Edgar181, Edward, Edward321, El C, Eleuther, Elliott707, Emil76, Eric119, Erik9, Esrever, Excirial, Falcon8765, Feline1, Felipe.erico.numerouno, Femto, Finlay McWalter, Firetrap9254, Flauto Dolce, Flewis, Fonzy, Frankenpuppy, Freakmighty, Freakofnurture, Frozenguild, Funandtrvl, FutureTrillionaire, GL, Gaius Cornelius, General robert e. lee II, Gentgeen, Giftlite, GimliDotNet, Ginga ninja 007, Ginsuloft, Glenn, Glrx, Gman4eva, GoingBatty, Graham87, Gtg204y, Gurch, Harp, Harryboyles, Headbomb, Hu, Hugo-cs, Hurricane111, Husayt, Hydrogen Iodide, IRP, Icairns, Ilahia, Immunize, Infrangible, IrishPete, Iskygge, Ixfd64, J.delanoy, JDDJS, Jan eissfeldt, Jauerback, Jauhienij, Jcf0810, Jeanne-charles, Jesanj, Jilkmarine, Jimp, Jmcferran, Joe Schmedley, John, Jonathunder, Joyous!, Julia giltner, nativity, Jusdafax, KChiu7, Kanthoney, Kazrak, Kbh3rd, Keenan Pepper, KnowledgeOfSelf, Kosebamse, Krawi, Kurykh, LA2, Lanthanum-138, LarryGilbert, Lcaa9, Lemons92, Leuko, Looxix, Lou.weird, M0rphzone, Mac Davis, Magioladitis, Malcolm, Malcolm Farmer, Manuel Anastácio, Marek69, Markhu, Markhurd, Materialscientist, MathewTownsend, Mattbr, Matthardingu, MattieTK, Mav, MaxSem, Mboverload, Mdlevin, Mean as custard, Megalodon99, Mejor Los Indios, Mewashere1, Mgiganteus1, Michael Hardy, Minimac93, Mjmcb1, Mlouns, Modify, Moonseer, Mpatel, Nakon, Nathybathy, NawlinWiki, Nergaal, Neutrality, Neverquick,
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 96
Niceguyedc, Nick Y., Nick911, Nitrogenoxide123, Obliterator, Ohconfucius, Oxymoron83, Parcly Taxel, Partnerintime12, Paul-L, Philip Trueman, Philthecow, Phuzion, Pine, Pinethicket, Ponder, Possum, ProhibitOnions, PrometheusX303, PublicPossum, Pyrochem, Qtothec, Quantumor, Qxz, R8R Gtrs, RIPCLB, RJHall, Radon210, Rajragavan, Rambam rashi, Ravichandar84, Razorflame, Rcachia, Reach Out to the Truth, Remember, Retostamm, Rettetast, RevRagnarok, Rex the first, Rfc1394, Rhobday, Rich Farmbrough, Rifleman 82, Rjwilmsi, Rob Hooft, Robchurch, Romanm, Ronhjones, Rory096, Rosarote elfe, Sam Li, Scerri, SchreiberBike, Scientific29, Scs, ShaunMacPherson, Shelter7, Shisha-Tom, Sirtrebuchet, Skatebiker, Skizzik, Smartse, Smashking77, Snowolfd4, Some jerk on the Internet, SpaceFlight89, Spellmaster, Spinningspark, Spoon!, Squids and Chips, Stardust8212, StaticVision, Stephenb, Stone, Stowy2, StringTheory11, SuperMagician, SwisterTwister, Tarquin, Tea with toast, The Thing That Should Not Be, The User 567, Thedjatclubrock, Theplanegeek, TheresJamInTheHills, Tide rolls, Titus III, Tnayin, Tohd8BohaithuGh1, Tommy2010, Tomos, Tomwalden, Tpbradbury, Tr-the-maniac, Trappleton, Tsange, Tsemii, Ucucha, Vanished user 39948282, Velella, ViolentRager, Vrenator, Vsmith, WOSlinker, WadeSimMiser, Watcharakorn, Wavelength, WaysToEscape, Whoop whoop pull up, Whosasking, Wikipedia brown, Winchelsea, Wtmitchell, Xdamr, Xentrion, YOSF0113, Yakudza, Yankeesrule3, Zarius, Վազգեն, 783 anonymous edits
Alkali metal oxide Source: https://en.wikipedia.org/w/index.php?oldid=509596730 Contributors: Double sharp, Whoop whoop pull up
Alkali metal halide Source: https://en.wikipedia.org/w/index.php?oldid=574457312 Contributors: Chemicalinterest, Chris857, Cyrek, Dirac66, Double sharp, HenkvD, J.delanoy, Naman kumar verma, Rifleman 82, Smokefoot, The way, the truth, and the light, Whoop whoop pull up, 21 anonymous edits
Periodic trends Source: https://en.wikipedia.org/w/index.php?oldid=593535343 Contributors: Al.Ilseman, Andrebolle, Antiowner, Aunva6, Azztech, Beetstra, Brammers, Calvin 1998, Chipmunkdavis, Chris the speller, Christian75, Cptmurdok, DVdm, DarkNiGHTs, DarkZealot89, DerHexer, Diannaa, Dotarulez2, Double sharp, Eastlaw, Epbr123, Flyguy649, Frozenport, Gegnome, Grey Matter, Isarra (HG), JForget, Jak86, JamesAM, Jamesbond12345, Jprg1966, Juliancolton, Kaldosh, Lanthanum-138, Lugia2453, M-le-mot-dit, Malcolma, Materialscientist, Matttoothman, Maxim Gavrilyuk, Metaknowledge, Mirek2, Mogism, Musicyea, Nerdygeek101, Nescalona, Nicoguaro, Ninjalemming, Nolookingca, Noosentaal, Omegakent, Paul August, Pratyya Ghosh, Puppydog12345, Reaper Eternal, Reelrt, Rettetast, Ribhavgupta, Rich257, Rifleman 82, Rocketrod1960, RoyBoy, Salehkn, Sciencegeekemc, Shultzc, Slightsmile, Somody, Stone, T-borg, Tetracube, Tfl, Th232, TheIguana, Tirtha bose12, Tnxman307, Truthanado, UndoMeister, Vanished user vjhsduheuiui4t5hjri, Wikipedian0791, William Avery, Yamamoto Ichiro, Yintan, Zontras Gry, 265 anonymous edits
Ionization energy Source: https://en.wikipedia.org/w/index.php?oldid=592642887 Contributors: Adjohnson916, Adrian.benko, Ahoerstemeier, Amqb, Arnobarnard, Az1568, BD2412, Bissinger, Blue william, Bomac, BrianGV, Bsdlogical, Calabe1992, Centrx, Chemicalinterest, Christian75, Chrisvelnet, Coasterlover1994, DMacks, DVdm, Dgw, Dirac66, Double sharp, DragonflySixtyseven, ELApro, Eastlaw, EdC2, Elassint, Electriccatfish2, Enduk, Epbr123, Femto, FourBlades, Ghewgill, Giftlite, Glane23, Glrx, Götz, H Padleckas, Hugo-cs, Iridescent, Itamblyn, Itub, J postlethwaite, J36miles, Jaxl, Jeff G., Jfrancis, Jhbdel, Jianhui67, Jim1138, John Cline, Jpark3909, Kbrose, Kkmurray, Kukini, Larryisgood, Legoktm, Leyo, LizardJr8, Lmp883, MagnInd, Majorly, Marek69, Mato, McSly, Mdhowe, Mediran, Mfwitten, MuZemike, Mushyrulez Alot, Namklim, Nanite, Ncmvocalist, Ndokos, NellieBly, Nivix, Nlanden, Nosferatütr, Oda Mari, Omegatron, PCHS-NJROTC, Pepper, Philip
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 97
Trueman, Piano non troppo, Pie4all88, Pifreak94, Pinethicket, Prodigalson12358, Pwjb, RGForbes, RJHall, Rainald62, Razimantv, Rhyshuw1, Rightsetter, Robert A. Mitchell, Roberta F., Ruolin59, Say2anniyan, ScAvenger lv, Sealbock, Shiney, Sirsparksalot, SkerHawx, Smokefoot, Storslem, Struway2, Sv1xv, Tal physdancer, Tariqabjotu, That Guy, From That Show!, The Original Wildbear, The Thing That Should Not Be, TheIguana, Tombomp, V8rik, West.andrew.g, Widefox, WikiUserPedia, XJaM, 278 anonymous edits
Electronegativity Source: https://en.wikipedia.org/w/index.php?oldid=590034187 Contributors: .:Ajvol:., 130.94.122.xxx, 2over0, AManWithNoPlan, Acroterion, Ahoerstemeier, Alapeds, Anoop.m, Anthony Appleyard, Arbitrarily0, Aronbeal, AySz88, Azo bob, Baijiab, Bcat, BeaumontTaz, Ben Tibbetts, BenAveling, BigGoose2006, Bizelburp123, Blackace1342, Bogey97, Bomac, Brentt, Brews ohare, Caiyu, Caltas, Casio93, Cdunn2001, ChemMater, Chodorkovskiy, Chris 73, ChrisGualtieri, Christian75, Chroniclev, Chymicus, Conversion script, Cuppy, Cww, Cyktsui, DMacks, Dakart, Dashed, DePiep, Deor, Deviator13, Dezidor, Dirac66, Discospinster, Djklein1431, Double sharp, DragonLord, Drkvncnt, Dtrebbien, Duffman15, Edward Z. Yang, El C, Elliott007kf, Elsweyn, Epbr123, Eric119, EtymAesthete, Excirial, Explicit, Favonian, Feline1, Femto, Foxj, Fra74, Frazzydee, Freak in the bunnysuit, Frigotoni, FrozenMan, Futbolplyr08, GPHemsley, Gaius Cornelius, Gene Nygaard, Gentgeen, Gertlex, Giftlite, Gilliam, Ginogrz, Giro720, Glane23, Graymornings, Gurch, HalfShadow, Happysailor, Harp, Haza-w, Hellbus, Heron, Heryu, Historical-critical method, Hut 8.5, Icairns, InternationalEducation, Iridescent, Itub, Ixfd64, JJ Harrison, JWB, Jeff G., JoanneB, Jon R W, Jorge Stolfi, Joyous!, Jtelser, Julesd, Jü, KBlott, KJS77, Karl-Henner, Keilana, Kfsung, King of Hearts, KnowledgeOfSelf, Krishnaprasaths, Kukini, Leujohn, Lfh, Lightmouse, Lim Wei Quan, MITBeaverRocks, Magnus Manske, Manicsleeper, Mannafredo, MarkSutton, Materialscientist, Merlion444, Mgiganteus1, Michael Hardy, Mira, Mojo Hand, MonoAV, Mschel, My back is wet, Mys 721tx, NKul, Nebular110, Neonumbers, NewEnglandYankee, NickCT, Ninjalemming, Normy rox, Oliphaunt, Omegatron, PL290, Pdienstm, Pepper, Peterwhy, Philip Trueman, Physchim62, Pichpich, Pion, Plasmic Physics, Pluma, Postglock, Prodigalson12358, Qxz, RJCoppin, Raistuumum, Rifleman 82, RockMFR, Rogper, Romanm, Ronhjones, Roy da Vinci, RoyBoy, Rqjj1502, Ryulong, Sam Hocevar, Sareen eng, ScAvenger lv, Sectryan, Senthryl, Seth Ilys, Shadowjams, Shellreef, Sjakkalle, Smartse, Snow Blizzard, Socob, Sodium, Somepostman, Spamicles, Spartaz, Sperxios, Stevey7788, Stone, Studying, Tarquin, Tassedethe, Tbhotch, TeejK, Tetracube, The Saad, The1physicist, TheTito, Thegamecreator1, Tim32, Tressor, Trusilver, Tsemii, Uncle Dick, Unyoyega, User27091, Vortigern, Vsmith, Vulcan Hephaestus, Vuong Ngan Ha, Walks17, Welsh, Whoop whoop pull up, Wickedclown29, Wickey-nl, WikiDonn, WikipedianMarlith, Wikipelli, Wimt, Winndm31, WinterSpw, Wipe, Xaosflux, Xeresblue, Yanwen, Youssefsan, Zeke pbuh, ^demon, Јованвб, وی کی ع لی, 에멜무지로, 508 anonymous edits
Melting point Source: https://en.wikipedia.org/w/index.php?oldid=590546203 Contributors: 13afuse, 3xtter, 5Q5, 8472, Ableakley, Acroterion, Adashiel, Addshore, Ahoerstemeier, Alansohn, Alfio, AliveFreeHappy, Andonic, Andre Engels, Andres, AnonHat, Antandrus, Arjun01, Art LaPella, Basawala, Bbanerje, Belovedfreak, Benbest, Benjah-bmm27, BesselDekker, Bidabadi, Biscuittin, Bobblewik, Bobo192, Bomac, BostonMA, Bryan Derksen, Bubba hotep, Bubbachuck, Burn, CJLL Wright, Callanecc, CambridgeBayWeather, Can't sleep, clown will eat me, Capricorn42, Cek, ChemMater, Cherkash, Chuckiesdad, Clicketyclack, Closedmouth, Comet Tuttle, Complexica, Cryonic07, Curps, D k mackenzie, DARTH SIDIOUS 2, DMacks, Danski14, Datapacrat, David.Monniaux, DeadEyeArrow, Denisarona, DerHexer, Dinesh smita, DinosaursLoveExistence, Dirac1933, Diverman, Double sharp, Dramartistic, Drthomasj, Dusique, El C, Epbr123, Everyking, Excirial, Felix Folio Secundus, Femto, FinalRapture, Fox Wilson, Fvw, GB fan, GTBacchus, Gene
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 98
Nygaard, Gentgeen, Geoffr, GianniG46, Giftlite, Gilgamesh he, Gilliam, Glacialfox, Glengarry, Glrx, GoShow, Gogo Dodo, Gonzonoir, Gracenotes, Greedysloth, GregorB, Grim23, Guocharles, Gurchzilla, Gwernol, Gzuckier, Harp, Hayabusa future, HereToHelp, II MusLiM HyBRiD II, IRP, Icairns, Ilovesinging101, Immunize, Iridescent, J.delanoy, JHunterJ, Jackfork, Jauhienij, Jawed, Jncraton, JoanneB, Joemoc, Johndburger, Josve05a, Jovianeye, Jpk, JuJube, Julesd, Kaiba, Kkmurray, Ktsquare, Kuru, La goutte de pluie, LeaveSleaves, Lights, Logger9, Lord Pistachio, MC10, Magog the Ogre, Marek69, Marie Poise, Mark Arsten, MarkGallagher, Martin Chaplin, Materialscientist, Matt Deres, Mediaghost, Merryjman, Mikaey, Mileystudy, Moogleydog, Mor, MusikAnimal, Mykhal, NHRHS2010, Newestcastleman, Nk, Nuggetboy, Nuno Tavares, Oakiedoke, Olivier, Oxymoron83, Ozzorro, PAR, Paikrishnan, Pb30, Pepper, Petermr, Pflatau, PhilKnight, Philip Trueman, Pinethicket, Pjanini1, Propaniac, R6MaY89, Radagast83, Radiojon, Ranveig, Reatlas, RexNL, Rhana13, Rich Farmbrough, Rickjpelleg, Rifleman 82, Rockfang, Romanm, Romney, Ronhjones, Rumostra, Scientific29, Scipex, Seba5618, Shirik, SiriusAlphaCMa, SmilesALot, Solid State, Some jerk on the Internet, State of Love and Trust, Stephenchou0722, Stereotek, Steve2011, StevenDH, THEN WHO WAS PHONE?, Tail, Techman224, The Thing That Should Not Be, Tide rolls, Torris, Touch Of Light, Tranletuhan, TravisTX, Trelvis, Trevor MacInnis, U.S.Vevek, Ugat, Unara, V.narsikar, V8rik, Van helsing, Vinne2, Waggers, Wavelength, Wioo, Woldo, Yintan, Zedshort, Zzuuzz, Јованвб, 507 anonymous edits
Boiling point Source: https://en.wikipedia.org/w/index.php?oldid=593012427 Contributors: 24.4.254.xxx, A8UDI, AVM, Abeg92, Academic Challenger, Acroterion, Aditya, Ahoerstemeier, Ajshm, Ale jrb, Amorymeltzer, Amp, Andre Engels, AndreNatas, Andres, Andy Dingley, Animum, Anonymous56789, Antandrus, Atarr, Ayla, Badgernet, Betacommand, BigDwiki, Bluemoose, Bmicomp, Bobblewik, Bobo192, Boing! said Zebedee, Bomac, Bongwarrior, Borgx, Bryan Derksen, BryghtShadow, Bubba hotep, Bunnyhop11, Burn, Buster2058, Can't sleep, clown will eat me, Capi crimm, Captain Quirk, Carlfork, Cek, Ched, Chris the speller, Christian List, Christian75, Complexica, Conscious, Conversion script, Cremepuff222, Crimsonfox, Cryonic07, DJ Clayworth, DMS, DMacks, Darth Panda, DavidFarmbrough, Dhp1080, DinosaursLoveExistence, Diomidis Spinellis, Dirkbb, Dlohcierekim, Double sharp, DoubleBlue, Draeco, Drthomasj, DéRahier, Edgar181, Edward, Eeekster, El C, EnSamulili, Epbr123, Eubulides, Everyking, Exor674, ExpiredEagle, Explicit, Fahadmeyo, Femto, Fieldday-sunday, Flamurai, Frym11, Fæ, GDonato, Gary King, Gatfish, Geekosaurus, Gene Nygaard, Gentgeen, Georgia guy, Giftlite, Go Phightins!, Gorank4, Gorgan almighty, GorillaWarfare, Gotta catch 'em all yo, Ground, Gurch, Götz, H Padleckas, HappyCamper, Harlem Baker Hughes, Harp, Hashar, Hdt83, Headbomb, Helikophis, Herbee, Heron, Howrealisreal, Husond, I dream of horses, I kabir, Iain99, Imapoed, InverseHypercube, Inwind, Italbar, J'88, J.delanoy, JLaTondre, Jared, Jatkins, Jauhienij, Jeff Carr, Jeremyb650, Jhbdel, Jim1138, John Palkovic, John of Reading, JorisvS, JrBr, Jusdafax, KGasso, Kaisershatner, Keegan, Kelly Martin, Kerowyn, Khazar2, Kuru, Kuyabribri, KylieTastic, Logan, Luna Santin, MONGO, Macarenses, Magnus Manske, Marek69, MarkGallagher, MarkSutton, Materialscientist, Mattrix, Mbeychok, Michael Devore, Mike Rosoft, Mike2vil, Moeron, Mormegil, Mr. Billion, Mukkakukaku, N5iln, Nakon, NawlinWiki, Nene cute, NewEnglandYankee, Nifky?, Nneonneo, Obenaza, Oda Mari, Ojigiri, Paikrishnan, Palica, Paul August, Pdcook, PhilKnight, Philip Trueman, PierreAbbat, Pinethicket, Prajwalvenkat, RL0919, Reconsider the static, Rhadamante, Rice.brendan, Ringbang, Rjwilmsi, Robert Rossi, Robma, Ronz, Roscoe x, RoyBoy, Rrburke, RunOrDie, RuudVisser, RxS, Ryan Postlethwaite, Ryan032, Salvio giuliano, SamuelRiv, Sanji Bhal, Scarian, Sciencompu, Shadowjams, Shanes, SirGrant, Skamecrazy123, Skysleeper1, Sleeper chevelle, Snowolf, Someone else, Spikey, Starwarsdarthmaul7, Stephenb, Sthomson06, Stifynsemons, Stismail, Stokerm, Stwalkerster, Substatique, Talveer, Tbhotch, Temporaluser, Tetracube, Th4n3r, The High Fin Sperm Whale, The Thing That
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 99
Should Not Be, TheBlueFox, TheKMan, Tide rolls, Tiggerjay, Tom harrison, Tomj, TonyW, Trurle, Trusilver, Unschool, Vary, Vazgen4, VegKilla, Velella, Versus22, Vsmith, WHeimbigner, WadeSimMiser, Watchdogb, Wavelength, Wayward, WhisperToMe, Widr, WilfriedC, Willking1979, Wimt, Wlerin, Woolstar, Wtmitchell, Zedshort, Zephalis, Zfr, Јованвб, 624 anonymous edits
Density Source: https://en.wikipedia.org/w/index.php?oldid=592607593 Contributors: *Kat*, 10014derek, 1028, 123Hedgehog456, 12dstring, 2over0, 3mta3, 42omle, 7, A8UDI, A930913, AAAFFF, AJR, AOC25, Abarrocks23, Abby, Acather96, Adashiel, Addshore, Adywilde, Afizah Osili, Afluegel, Aguner, Alansohn, Alex Bakharev, Alexanderthorntonsmith, AlexiusHoratius, Alexjohnc3, Alexonly9, Alexselkirk1704, Alison, Alksub, Altamash3000, Alterro, Ammodramus, Anacario, Andeggs, Andre Engels, Andrevan, Andrewman327, Ankurtg, Antandrus, Antipastor, Antiqueight, Antonyk, Arabinator, Arjun01, Arosa, Arvindn, Asacen, Astroview120mm, Atif.t2, Austinestes67, Autumgirl, Avoided, AxelBoldt, BD2412, BRW, BW95, Babakathy, Bart133, Beeblebrox, Ben pcc, Ben-Zin, BenC7, BenFrantzDale, Benjicharlton, Bensaccount, Berland, Bernd Gloss, Bernster1, Bhny, Bihco, Blacklite, Blanchardb, Blaxthos, Blind cyclist, Bob the Wikipedian, Bobo192, Boby9952, Bodil, Bogey97, Bomac, Bongwarrior, Book maniac, Born2killx, Brazzy, Brian0918, Brookie, Bryan, Bryan Derksen, Bsadowski1, Bulba2036, C'est moi, C6541, CA387, CP\M, CWenger, Cadari09, Calabe1992, Calmer Waters, Caltas, CambridgeBayWeather, Can't sleep, clown will eat me, Captain Climber, spec-zero, of Ion Team, Casper2k3, Catgut, Cferrero, Chaosfeary, CharlesWemyss, Chem2410, Chris goulet, Chris the speller, ChrisGualtieri, Christian75, Chubbles, Church, Cindamuse, Cky2250, Clarince63, Closedmouth, Cmglee, Cmichael, Colpitz, Conversion script, Corvus cornix, CountMacula, Courcelles, Crazydotz12, Cremepuff222, Ctg4Rahat, Cunard, Cupcakecutie, Cutler, Cyktsui, D. Recorder, DARTH SIDIOUS 2, DMacks, DaL33T, Dancter, Dannyb2k, Darth Panda, Davewho2, DeadEyeArrow, DeadlyAssassin, Deanos, Dekimasu, Delusion23, Demmy, Denisarona, Depictionimage, DerHexer, DexDor, Dhollm, DigitalCatalyst, Dilmaster79, Discospinster, Djd sd, Donner60, Dougofborg, Dr. Whooves, Dudecon, Dungodung, Dwikiv, Dycedarg, Dylan620, E-jim, ERcheck, ESkog, Edgar181, Eeekster, Eequor, Efiiamagus, Ehdr, Ehrenkater, Ejke47, Electron9, Elen of the Roads, Eliyak, Emersoni, Emote, Emperor Will, Emperorbma, Epbr123, Er Komandante, Ergative rlt, Eric-Wester, Erikev, Escape Orbit, Eumolpo, EuroCarGT, EvelinaB, Everyking, Excirial, FF2010, Fabrictramp, Falcon8765, Fatima442, Feezo, Femto, Fibula, Firebladed, Flag cloud, Flippin42, Flockmeal, Flowerpotman, Flyboy 185, Fnlayson, Fo real223, Fraggle81, Freallapousdubious, Fredil Yupigo, Friginator, Frosted14, Frozenevolution, Fæ, GPoss, Garyzx, GavinTing, Gcllau, Gene Nygaard, Generalcp702, Gentgeen, Geoberry1997, Giftlite, Gimligimli, GlassCobra, Glenn, Godjesusman, Gogo Dodo, Goofylookingkid, Gr1st, Grafen, GrahamDavies, Grayshi, Greenguy1090, Grim23, Gryllida, Gurch, Guyzero, Gwernol, Götz, HMSSolent, Hadal, Hagerman, Haham hanuka, Hahamiayah, Haiviet, Hall Monitor, Halmstad, Happyfunfun12, Hardyplants, Harland1, Hdt83, Headbomb, HeartofaDog, Heimstern, Helping39, Heron, Heymid, Hibisco-da-Ilha, Hicloudx, Higuysmyname, Himan42, Hlipsky5, Hobartimus, Hungda, Hunter1602, Hurricanefan24, Hut 8.5, Huwnet, I am One of Many, I dont know what's going on, I dream of horses, IVAN3MAN, Ian.thomson, Icairns, Ike9898, Immunize, Indon, Inkowik, Insanity Incarnate, Instinct, Interstellar Man, Into The Fray, InvaderJim42, Ioscius, Iridescent, Isarra (HG), Ixfd64, J'88, J.delanoy, J1i1m1m1y1, JForget, JJ Harrison, JSquish, Jackmcbarn, Jackol, Jamamala, James086, JamesBWatson, Jamesx12345, Jan van Male, Jasondet, JavierMC, Jeroboambramblejam, Jeronimo, Jespinos, Jezhotwells, Jh51681, Jim1138, JimChampion, Jj137, JoanneB, Jochoa22, JodyB, JoeSmack, John254, Jonathan888, Jorcoga, Josh Parris, Jossi, Jr226, JunCTionS, Jusdafax, Just plain Bill, Justin W Smith, KC109, Kapik, Karl Dickman, Karl-Henner, Karlhahn, Karol Langner, Karonaway, Katana, Kate, Katieh5584, Kaya49, Kazayta, Kdavidk, Keegan, Kelvinsong, Kerina yin, Kevin12xd, Kimon, Kimyu12, Kingkong654,
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 100
Kolbasz, Kristen Eriksen, Ks0stm, Kukini, Kuru, Kurykh, Kusma, L Kensington, L3wl, LBJtheking, LFaraone, LaggedOnUser, Lars, Laurascudder, Lefticle, Lenaic, Lerdsuwa, Lerner.hu, LiDaobing, Lights, Likeyah64, Linas, Lio, Little Mountain 5, LittleOldMe, Lkjhgv, Lolnerds, Lololonie, Longhair, Loren36, Lradrama, LucasVB, Lugia2453, Luk, Luna Santin, Lupin, MBisanz, MC10, MER-C, MONGO, Macintosh User, Macy, MadGuy7023, Madchester, Magioladitis, MagnInd, Malcolm, Malcolm Farmer, Malo, Mani1, Marcozezianliz, Marek69, Mark Arsten, MarsRover, Martin Holecek, Martin451, Martinp, Marzia mitu, Massimo377, Master of Puppets, Materialscientist, Matt B., Mav, MaxEnt, Maxim, Maximus Rex, McSly, Mdebets, Meis4bf, Melchoir, Melsaran, Mercredi-Soir, Merlion444, Merovingian, Metahacker, Mezzon, Michael Hardy, MichaelMaggs, Mikael Häggström, Mike Rosoft, MileyFan14, Minesweeper, Minimac, Mmoneypenny, Mojo Hand, MrZhuKeeper, Mrbrtk, Muhandes, Muro de Aguas, Mwtoews, Myanw, Myomancer, NHRHS2010, Naddy, NathanHurst, NativeForeigner, Natural Philosopher, NatusRoma, NawlinWiki, Nbarth, Neko-chan, Neuroaudio, Neverquick, NewEnglandYankee, Nickkid5, Night Gyr, Nikkimaria, Nish81, Nivix, Nneonneo, Northumbrian, O.Koslowski, Ocaasi, Ocean dreamzz, Oceanlakesskater, Octane, Oda Mari, Odie5533, Oneiros, Oxymoron83, PL290, Pae nor, Paikrishnan, Pairadox, Pakipaki2000, Patrick, Paulleggett, PeaceNT, Pepsi1, Perfect Proposal, Person1997, Peterlin, Petrb, Pewwer42, Phailboat, Pharaoh of the Wizards, Philip Trueman, Piano non troppo, Pigalle, Pinethicket, Pingveno, Pizza Puzzle, Pjacobi, Pol098, Porqin, Pppenmwinefondf, Princess180, PrincessofLlyr, Pro bug catcher, Pseudomonas, Psy guy, Psyche825, Pushkar.gaikwad, Quercus basaseachicensis, QuiteUnusual, Quiztester, Qwerty Binary, RHaworth, RJaguar3, Rainer Bartoldus, Rama, Random832, Raptus Regaliter Cattus Petasatus, Razorflame, Rdsmith4, Reatlas, Reconsider the static, Red Denim, Redrose64, Retiono Virginian, RexNL, Reywas92, Rhetth, Rhobite, Rich Farmbrough, Richmond96, RickK, Roentgenium111, Romanm, Ronhjones, Ronline, Rosa67, RoyBoy, Rrburke, Rtdrury, Rumping, Rwxrwxrwx, SEWilco, SJP, Saddy Dumpington, SajmonDK, Salih, Sandman962, Sango123, Sarranduin, Satellizer, Sbowers3, Sceptre, SchfiftyThree, Sciurinæ, Seanken, Seba5618, Sedimin, Seijihyouronka, Shadowjams, Shanata, Shandris, Shantosaur, Shinpah1, Shizane, Sholto Maud, Sigmundg, Sillybilly, SilverSB, SimonP, Simon_J_Kissane, Simskl, Sionnach1, Skarebo, Sky Attacker, Skyezx, Slakr, Sleeping123, Slightsmile, Smilesfozwood, Snowolf, Softwarestorage, Sonett72, SouthernNights, SpK, SpaceFlight89, Spacepotato, Spiffy sperry, SpookyMulder, SpuriousQ, Staeiou, Stan J Klimas, Steinsky, Stephan Leclercq, Stephenb, Steve2011, StevenJohnston, Stevertigo, Stickee, Stifynsemons, Stokerm, Suffusion of Yellow, Sunnyquinn12, Supadawg, SuperHamster, Superboy112233, SusikMkr, SwisterTwister, Synchronism, Syndicate, THEN WHO WAS PHONE?, TStein, Taeedxy, Tail, Taj722, TakuyaMurata, Talon Artaine, Tarotcards, Taskualads, Tbhotch, Tbmoney1000, Teapeat, Tentinator, Terence, Terminator484, TerryAga, TestAccount45678, Tgeairn, The Anome, The Canadian Roadgeek, The High Fin Sperm Whale, The Mad Genius, The Rock And Roll Pirate, The Thing That Should Not Be, The wub, TheDJ, Thedjatclubrock, Thegreatdr, Thestraycat57, Tiddly Tom, Tide rolls, TigerShark, Tim-lees, Titoxd, Tjorgensen, Tkasmai, Tom harrison, Tomasr, Tomásdearg92, Tone, Totalporch2, Towel401, Trasmuss, Tregoweth, Tresiden, Triwbe, TwistOfCain, Tyyeerr, UberScienceNerd, Uellue, Ufwuct, Ugur Basak, Ulric1313, Uncle Dick, VanBuren, Velella, Verazzano, Versus22, Vipinhari, Vishakh tiger, Vsmith, Vssun, Vystrix Nexoth, Wapcaplet, Warlordwolf, Wasbeer, Wavelength, Wavgfkl, Wayne Slam, Webclient101, Weedwhacker128, WereSpielChequers, WhisperToMe, WhiteAtlas, Wic2020, Wik, WikiFew, Wikianon, Wikibofh, Wikimabi, Wikinick, Wikipelli, Wildthing61476, WilfriedC, WillowW, Wimt, Wocky, Wolfkeeper, Woodsstock, Wtmitchell, X!, XDfunnyface, Xezbeth, Xplosivechiken, Y2H, Yadevol, Yamamoto Ichiro, Yekrats, Yintan, Yoshigev, Zaidpjd, Zenibus, Σ, 2272 anonymous edits
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 101
Ununennium Source: https://en.wikipedia.org/w/index.php?oldid=590007437 Contributors: 3.14159265358pi, Aherunar, Alan Liefting, Allen3, Amalas, Animal Titans, Anthony Appleyard, AuroraReloaded, Avicennasis, Bender235, Bhangranuch, Bueller 007, Burzuchius, Cax17, Cfailde, ChemNerd, Chillysnow, Chris Henniker, Complex01, Connormah, Cosmium, DMacks, Darrien, David Latapie, Db099221, Dcorrin, DePiep, Deflective, Dex1337, Difluoroethene, Double sharp, DoubleBlue, Drjezza, Drmies, E23, Eddy1305, Edgar181, Emperorbma, Eric119, Femto, Feneeth of Borg, Fiveless, Fonzy, Frencheigh, Gcchemistry, Georgia guy, Gertlex, Gogo Dodo, Headbomb, Honeycake, Hopfer25148, INVERTED, Ixfd64, Jab416171, Jacob S-589, Jagro, Jasper Deng, John, JohnyDog, Jprg1966, Karlchwe, Kate, Keenan Pepper, Kelovy, Kurykh, Kwamikagami, Lanthanum-138, Larry laptop, Leptictidium, Lysdexia, Magioladitis, Materialscientist, Mav, Meeper27, Mike Rosoft, Mikespedia, Miranche, Moe Epsilon, Mxn, NawlinWiki, Nergaal, NickBush24, Nihiltres, Nimbulan, Nirmos, Oppertunity, Ortolan88, PlanetStar, Plasmic Physics, Plutoplanet, Poolkris, Redrose64, Rjwilmsi, Roentgenium111, Runwithchemicals, Scienceguy2005, Srinivasasha, Stone, StringTheory11, Su-no-G, Superheavy120, TheRabidMonkie, Timc, TitanOne, Tommy2010, Tomwalden, Tresiden, Trixt, Veritaslux, Vsmith, Warut, Whoop whoop pull up, Wikianon, Wikipelli, Yewlongbow, גלעדי ינון, 160 anonymous edits
Hydrogen Source: https://en.wikipedia.org/w/index.php?oldid=593219848 Contributors: (jarbarf), -- April, -jmac-, 0kdal, 123456mf, 16@r, 1Martin33, 65.68.87.xxx, AManWithNoPlan, AOC25, AStudent, Abarry, Abdulwahabmalik, Abyssadventurer, Acerty123, Acroterion, Acwrobel1, Adambro, Adashiel, Addshore, Adimovk5, Adrignola, Aervanath, Ahoerstemeier, Aitias, Akusarujin, Alejandrocaro35, Alexf, AlexiusHoratius, Allstarecho, Alrasheedan, Alsandro, AmericanLemming, Ancheta Wis, AndreasJS, Andrei Ramanonov, Andres, AndrooUK, Andy M. Wang, Anonymous56789, Antandrus, Anthony Appleyard, Archimerged, Aristophanes68, Aristotle28, Army1987, Arsonal, Ashill, Ashmedai, Ashmoo, Atelaes, Atlant, Attinio, AvicAWB, Awesome monk, AxelBoldt, AySz88, AzaToth, BAZZA42, BBird, BD2412, BRG, Balgontork, Basicdesign, Bcorr, Beetstra, BenFrantzDale, Bender235, Benjamin1414141414141414, Benjamnjoel2, Benji Franklyn, Bensaccount, Bgwhite, Bibbidbabbidi, BigBen212, BiggKwell, Bkell, Blacklemon67, Blahbleh, Blainster, Blimpguy, Blind Man Walking, Blurpeace, Bobo shnob, Bobo192, Boldra, Bongitybongbong, Bookandcoffee, BorgQueen, Borgdylan, Bowei Huang 1, Bpeps, BradBeattie, Brandonrush, Bravehart10000, BrightStarSky, Brighterorange, Bryan Derksen, Bsadowski1, Buckyboy314, Bunnyhop11, Buster79, Bù hán ér lì, C'est moi, CPColin, CStyle, CYD, CalicoCatLover, Callumgare, CambridgeBayWeather, Cameron Nedland, Can't sleep, clown will eat me, Canageek, CaptainVindaloo, Carlobus, Carnildo, Casull, Celarnor, CephasE, Cerealkiller13, Cfailde, ChaoticLlama, Charles Gaudette, Chemkid1, ChicXulub, Chochopk, Chowbok, Chris Dybala, Chris Henniker, Chris the speller, ChrisGualtieri, Chrisjj, Chrislk02, Christian75, Christopher Parham, Chzz, Cimbalom, Civil Engineer III, Cktt13, Clicketyclack, Code E, Colbuckshot, Colonies Chris, Commander Keane, CommonsDelinker, Condem, Contango, Conversion script, Coppro, Corporal butters, Cosmium, Costyn, Coviekiller5, Crescentnebula, Cryptic, Cryptic C62, CuriousEric, Cwkmail, Cybercobra, CyclePat, Cyclotronwiki, Cyrius, D. F. Schmidt, DARTH SIDIOUS 2, DJ Clayworth, DJIndica, DLH, DMacks, DR. R leris, DSS370, DV8 2XL, DVD R W, DabMachine, Dagistansahin, Dagvidur, Damian805, Dammit, Dan East, Daniblanco, Daniel5127, Danny, Dannyc77, Dark Shikari, DarkCatalyst, Darrien, DaveOinSF, Daveoh, Davewild, DavidJKim, Davidkazuhiro, Ddon, DePiep, Deflective, Deglr6328, Deli nk, Delta G, Denali134, Denisarona, Deor, Deorum, Digger3000, Digitalme, Dina, Dirac66, Divydovy, Dlohcierekim's sock, Dmoss, Dogposter, Dominus, Donald Albury, Double sharp, Dpotter, DrKiernan, Drakcap, Dreaded Walrus, Drfool, Dwmyers, EJF, EL Willy, EZ, Edgar181, EdgeOfEpsilon, Edsanville, Edwincespedes, Ee00224, Ehrenkater, Ekrub-ntyh, El C, Elb2000, Eldawg, Eldin raigmore, Eleassar777, Emperorbma, Emre D., Emurphy42,
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 102
Eng02019, Environnement2100, Epbr123, Epiphanic, Eric Kvaalen, Eric119, Erick880, Ericoides, Erik Zachte, EryZ, Esrob, Eugene van der Pijll, EugeneZelenko, Evand, Evercat, Everchanging02, Everyking, Ewen, Eyu100, FF2010, FT2, Facka, False vacuum, Fatal error, Favonian, Fdot, Feezo, Femto, FengRail, Fg2, Fighterf4u, Finalius, Flyguy649, Fonzy, Forderud, FrancoGG, Frankyboy5, Free4umatt, Frood, FrummerThanThou, Fsotrain09, Funion987, FvdP, GCarty, GDW13, Gadolinist, Gaius Cornelius, Galaksiafervojo, GamemasterXX, Gargoulf, Gcsuchemistry, Gdo01, GeeJo, Gene Nygaard, GeneralHooHa, Geni, GeorgeLouis, Gianluca.valenti, Giftlite, Gilgamesh, Gjd001, Glen, Glenn, Gman124, Go229, Gogo Dodo, Goldzahn, Golfit, Gproud, Grace Note, Gracefool, Gracenotes, Graeme Bartlett, Graham87, Gravitan, Greater mind, Grendelkhan, Grika, Grrahnbahr, Guanaco, Gurch, Gurps npc, Gwernol, Gyrobo, HJ Mitchell, Hackwrench, Hadal, Hadavid52, Hak-kâ-ngìn, Hankwang, Hdt83, Headbomb, Hemanshu, Herbee, HereToHelp, Heron, Hibernian, Hindro, Hodeken, Holoman, Honi, Hu, Hurricane Angel, Husond, Hv, Hydrogenlol, Iain99, Iamwhite, Iantresman, Icairns, Iluallen94, Instinct, Inwind, Ioscius, Irishguy, IronGargoyle, Isilanes, Itamblyn, Itsmine, Itub, Ixfd64, J.M.Domingo, J.delanoy, J3ff, JForget, JFreeman, JG90620, JNW, JSquish, JabberWok, Jacek Kendysz, JahSun, Jakohn, James086, Jaraalbe, Jaranda, Jasper Deng, Jasz, Jauerback, Jaxal1, Jaxl, Jay32183, Jcw69, Jdigangi, Jdurg, Jeffness, Jezerfetnae, Jim1138, Jimp, Jnargus, JoanneB, Joelr31, Joey711, Joeylawn, John, John Reaves, John Vandenberg, JohnHSand, JohnSRoberts99, Johnbrownsbody, Johnflux, Johnfos, Jon Harald Søby, Jorge Stolfi, Jose77, Josh dsouza5, Joshschr, Joyous!, Jpbuccat, Jredmond, Jrockley, Jsroberts, Jtgibson, Jumbuck, Junglecat, Jusdafax, Just Another Victim Of The Ambient Morality, Jwratner1, KJS77, Kahleflower93, Kaimakides, Kaisershatner, Kaldosh, Kalibanos, Kargoneth, Karn, Karol Langner, Katalaveno, Kbh3rd, Kchishol1970, Keilana, Keith D, Kenb215, Kesac, Killthemonkey, King of Hearts, Kingoffries7, Kingturtle, Kinu, Kjkolb, Kkosman, Klosterdev, KnowledgeBased, KnowledgeOfSelf, Kontar, Kpjas, KrakatoaKatie, Kralizec!, Krash, Kristod, Ktsquare, Kungfuadam, Kuru, Kuyabribri, Kwamikagami, Kwksi, L Kensington, LA2, LHcheM, Lacrymachristi, Lanma726, Larry Sanger, LeadSongDog, LegitimateAndEvenCompelling, LeonardoRob0t, Lesnail, Levil, Lewis R, Lfstevens, Libraryopolis, Lightdarkness, Lightmouse, Lights, LilHelpa, Linnell, Littlecode, Lkc159, Llamallama, Loonymonkey, Lord Emsworth, Lotje, Luna Santin, Lyellin, Lysdexia, M11101, MJCdetroit, MZMcBride, Mac, Maestro52193, Magicjigpipe, Magioladitis, Magister Mathematicae, Magnus Manske, Mahlonmahlon, Majorly, Malomeat, Mangersz, Marcus Qwertyus, Mark10101, Marnanel, Marskell, Maseracing, Master of Puppets, Matanbz, Materialscientist, Matt Gies, Matt McIrvin, Mattd4u2nv, Mav, Maximus Rex, Me...™, Meaghan, Mesmoras, Meteor sandwich yum, Mets501, Michaelas10, Michaelbarreto, Michaelbusch, Mikael Häggström, Mike Rosoft, Mike Young, Mike6271, Mikecron, Mikewille54, Mild Bill Hiccup, Minesweeper, Minus198, Mion, Mkosmul, Mmortal03, Moeron, Monre, Mr. Lefty, MrZap, MuchForgottenLore, Mufka, Muqman 52, Muqtasidmansoor, Mxn, Naddy, Nakon, Nao1958, NarSakSasLee, Nat Krause, Nationalparks, NawlinWiki, NeiallsWheel, Neptune5000, NerdyScienceDude, Nergaal, Netizen, Neverquick, NewEnglandYankee, Nibuod, Nick2588, Nicola.Manini, Nigenet, Nihiltres, Nilfanion, Nintendofanatic, Nishkid64, Njál, Nk, Nkayesmith, Nolanus, NonChalance, Nono64, Noren, Northumbrian, Notea42, NuclearWarfare, OSU1994, Oatmeal batman, Obradovic Goran, Oddity-, Oliphaunt, Oliverkeenan, Olivierd, Omegatron, Omicronpersei8, Onco p53, Oo64eva, Oofgeg, Opabinia regalis, Opelio, OrangeDog, Oscarthecat, Ossi, Outflowboundary, OwenX, Oxymoron83, P. S. F. Freitas, Paine, Papa November, Paraballo, Parcly Taxel, Partapdua1, Patrick, Patstuart, Paul August, Paul MacDermott, Pcbene, Persian Poet Gal, Peter Ellis, PeterJeremy, Pgk, Phenz, Phil Boswell, Phileas, Philosopher, Phung Wilson, PhySusie, Physchim62, Pifreak94, Pika32141, Pinethicket, Pkpat2011, PlanetStar, Plantsurfer, Plasmic Physics, Polymerbringer, Poolkris, Porges, Postdlf, Poszwa, Pr0f3550r, Probus, Prodego, Proton44, Pschemp, PseudoOne, PseudoSudo, Pstanton, Psyche825, Public Menace, Puffin, Pumpie, Pwjb, Pyrotec, Qsdf, Quadell,
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 103
Quadpus, Quaeler, Quinacrine, Qxz, RB972, RJASE1, RJHall, RMHED, RTC, RUL3R, Radon210, Radu Gherasim, Raeky, Raghunathan, Ralesk, Rallette, Ramendoctor, Rangek, Raul654, Ravedave, Ravn, Rdsmith4, Reallybadtrip, Reatlas, Reedy, Regardless143, RegentsPark, Rei, Remember, Renesis, Revotfel, RexNL, Rhobite, Riana, Rich Farmbrough, Richardglendenning, RichiH, Rifleman 82, Rjhansen, Rjmx, Rjwilmsi, Rklawton, Rlandmann, Robbin' Knowledge, Robert the Devil, RobertAustin, RobertG, Robth, Rocio Nadat, Rockfang, RossPatterson, RoyBoy, RoyGoldsmith, Rrburke, Rttd411, RucasHost, Rursus, Ruud Koot, Ryankrameretc, Ryanwammons, Ryulong, SCEhardt, SETIGuy, SEWilco, SJP, ST47, SalopianJames, Salsb, SaltyBoatr, Samesjr, Samsara, Sandy of the CSARs, SandyGeorgia, Sanfranman59, Sango123, Saperaud, Sarvagna, Saxman97, Sbharris, Scarian, Schneelocke, Schutz, Scog, Scot.parker, Scwlong, Seb az86556, Securiger, Sengkang, Senor Cuete, Sensen, Sewings, Shadow7789, Shambolic Entity, Shanel, Shanes, Shellreef, Shep9882, Shiftmain7, Shimmin, Shinkolobwe, Shizane, Shrikethestalker, Sietse Snel, Sigurdur.j, Sillybilly, SimonP, Sio6627, Skier Dude, Sl, Slash, Slippered sleep, SlowJog, Smokefoot, Sno2, Snoyes, Solitude, Someone else, Someoneinmyheadbutit'snotme, Sonofabitch, Soulkeeper, Soyluismofo, SpaceFlight89, Spacepotato, Spangineer, Spiff, Splarka, SpookyMulder, Sportzplyr9090, SpuriousQ, Squids and Chips, Squirepants101, Srich32977, Srtxg, Ssilvers, StAnselm, Stagyar Zil Doggo, Steel, Steinbach, Stephen G. Brown, Stephenb, Steve Hart, Stiaand, Stijndon, Stokerm, Stone, Strait, Streetsabre, Suffusion of Yellow, Suisui, Sunborn, Supten, Suruena, Susurrus, THF, TRosenbaum, TX-TransAm, Tac2z, Tad Lincoln, Talibanftw, Talon Artaine, Taroaldo, Taweetham, Tawker, Taxman, Tbhotch, Teentje, Teratornis, Terra Xin, Texture, The Anome, The Bushranger, The Great Zo, The Rambling Man, The way, the truth, and the light, The-G-Unit-Boss, TheRingess, TheSun, Thegreenroo, Theinfamousfinatic, Thesatirist, Thirteenangrymen, Thricecube, Thumperward, Tidaress, Tiddly Tom, Tim Starling, Timo Honkasalo, Tiptoety, Tobby72, Tom harrison, Tomgally, Tomos, Tompsci, Tomtheman5, Tony1, TonyMath, Torgo, Totalllgeek, Totlmstr, Touriste, Tpbradbury, TranClan, Traroth, Trelvis, Trevor MacInnis, Treyt021, Trojancowboy, Trovatore, Truthanado, TutterMouse, Tysalpha, UB65, UBeR, Ufwuct, Ungvichian, Urhixidur, Uruiamme, User A1, Utcursch, Valencerian, Vanderdecken, Vanished user 90345uifj983j4toi234k, Vegaswikian, Velociostrich, Viddin66, Viskonsas, Vlectric, Vortexrealm, Vsmith, Vssun, Vuo, WAS 4.250, WJBscribe, WadeSimMiser, Waffleguy4, Waggers, Walkerma, Walton One, Warrenokeefe, Watch37264, Wavelength, Wayward, Webguy, Wednesdaymorning3am, WelshMatt, Whirling Sands, Whoop whoop pull up, Wii Wiki, Wiki alf, Wikibob, Wikicali00, WikipedianMarlith, Wikipediarules2221, Wikispork, Wikisyzygy, Wikiwert, William Allen Simpson, WillowW, Wimt, Wk muriithi, Wms editor, Wolfkeeper, Wtshymanski, Wyllium, XJaM, Xaoa, Xenonice, Xevi, Xeworlebi, Xnuala, Xyzzyplugh, Yamamoto Ichiro, Yath, Yidisheryid, Yinon, Yorktown1776, Zach4636, ZayZayEM, Zoe, 1585 anonymous edits
Ammonium Source: https://en.wikipedia.org/w/index.php?oldid=579084858 Contributors: A. Parrot, A876, ABCD, Alaniaris, Allens, Andre Engels, Anomalocaris, Anthony Appleyard, Balloonguy, Bellerophon, Benjah-bmm27, Berkay0652, Bishopredinghigh, Brockert, Cacycle, Can't sleep, clown will eat me, Chemicalinterest, Chris the speller, Chris857, Christian75, Chsf, DQJK2000, Davecrosby uk, Deli nk, Demortes, Devrit, Dj Capricorn, Double sharp, Dvdgc, E Wing, ERcheck, Edward Z. Yang, Eequor, Fierywindz, Francvs, Gabethenerd, Gentgeen, Gilliam, Glenn, H Padleckas, Haikon, Hellbus, Hubba, Iantresman, Infophile, Isidore, Isnow, J.delanoy, JSquish, JamesAM, Jfdwolff, Jimp, Joanjoc, Joshganga, Juliancolton, Keenan Pepper, Krasnoludek, La goutte de pluie, Leyk17, Louisajb, MPerel, Malbi, Materialscientist, Mav, Maxim, Maximus Rex, Mentifisto, Mikael Häggström, MikeLynch, Mikespedia, Mild Bill Hiccup, Milnivri, Miraculousrandomness, Nakon, Nihiltres, Nirmos, Nk, Onco p53, Opelio, Oreckel, Paolo.dL, Paul Erik, Peruvianllama, Phatom87, Physchim62, PierreAbbat,
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 104
Pinethicket, Plasticup, Plumbago, Pol098, Psyche825, Px31fw, Raoul NK, Rezecib, Rifleman 82, Rjwilmsi, SanitysEdge, Scott McNay, Seaphoto, SlightlyMad, Smettems, Smokefoot, Spike Wilbury, Splee, Tetracube, Tgeairn, The High Fin Sperm Whale, Thegreenj, Thingg, Tideflat, Tolly4bolly, Trusilver, V8rik, Vacuum, Valacosa, Walkerma, Wavelength, Wickey-nl, Wiki alf, Wimvandorst, Xris0, Yakudza, ZooFari, 173 anonymous edits
Thallium Source: https://en.wikipedia.org/w/index.php?oldid=593144871 Contributors: 21655, 28421u2232nfenfcenc, APerson, Aarchiba, Achaemenes, AdjustShift, Aecis, Ageo020, Ahkond, Ahoerstemeier, Alchemist-hp, Alex.tan, Alvis, Amaury, Andre Engels, Andros 1337, Antandrus, Arabani, Arcadian, Archimerged, Arkuat, Astanhope, Astatine-210, Barsoomian, Bayou Banjo, Bbartlog, Belg4mit, Bender235, Benjah-bmm27, Benjamin Mako Hill, Bernd.Brincken, Binky, Blah27, Blueshirts, Borishal, Brockert, Brutaldeluxe, Bryan Derksen, Bwrs, CSWarren, CWii, CYD, Carnildo, Cburnett, Cecil, Cgingold, Ch'marr, Chasingsol, Chemicalinterest, Chris the speller, Christian75, Cmdr Scolan, Conversion script, Courcelles, Cwkmail, Cybercobra, DabMachine, DadaNeem, Dajwilkinson, Darrien, Davemcarlson, David Haslam, David Latapie, DePiep, Deflective, Delirium, Deutschgirl, Difluoroethene, Diwas, Doggie389, Donarreiskoffer, Double sharp, Dr Zak, DrBob, Dragonich777, Dschwen, Duja, Dysprosia, EagleFan, Edgar181, El C, Element16, Eleveneleven, Elfbunniegirl, Emperor, Emperorbma, Enok Walker, Eric119, Erik Zachte, EvelinaB, Everyking, Excirial, Fabiform, Facts707, Feline1, Femto, Firedrop, FlyingPenguins, Froth, Fvasconcellos, GT5162, Gene Nygaard, Gilliam, Globe Collector, Gnfnrf, Gogo Dodo, GoingBatty, Gproud, Graham87, GrahamHardy, Greatpatton, Greg Lindahl, Grendelkhan, Groyolo, Grumpyoldgeek, Gypsypkd, Gyrobo, Hak-kâ-ngìn, HappyCamper, HazyM, Headbomb, Hede2000, Helge Skjeveland, Hellbus, Hippietrail, Hofoen, Huji, Icairns, Ideyal, Igoldste, Itub, J.delanoy, JALockhart, JZNIOSH, Jacj, Jaelanrodriguez, Jaraalbe, Jasper Deng, Jauhienij, Jd027, Jennyvu96, Jfromcanada, Jimbimedia, Joanjoc, Johantheghost, John, John Nevard, John of Reading, Josh, Josh Parris, Jsjxyz, KRSESQ, Karlhahn, Kcjenner, Kelisi, Kipholbeck, Kostmo, Ksaraf, Kurykh, Kwamikagami, Lamro, Liam Skoda, Linmhall, Liontooth, Lizzie Harrison, Looxix, LorenzoB, Lpnsm1, Lumos3, Madder, Malcolm Farmer, MapsMan, Marc Venot, Markjoseph125, Materialscientist, Mattfiller, Matthew0028, Mav, Mccready, Michael Frind, Michael Snyder, MightyWarrior, Mikael Häggström, Minesweeper, Mortdefides, Mr Minchin, Msjayhawk, Mygerardromance, NReitzel, NT17, Nabokov, Naddy, Namibnat, Neparis, Nergaal, Neverquick, Ngebendi, Nickkid5, Nihiltres, Niro5, Nuclearmedzors, Ojs, Oliverkroll, Omicronpersei8, Oobopshark, Orange Suede Sofa, Ortolan88, Oskar Wallströmer, OwenBlacker, Oxymoron83, Panthro, Paraballo, Parcly Taxel, Petri Krohn, PhilHibbs, PigFlu Oink, PlanetStar, PlatinumX, Poccil, Polonium, Poolkris, Prari, Proofreader77, Quadro, Quebec99, Qwfp, R8R Gtrs, RTC, Racerx11, Raghav273, Reatlas, Remember, Rjwilmsi, Roberta F., Rocketrod1960, Romanm, Rossami, SHCGRA Max, Saperaud, Sbharris, Sbmehta, SchfiftyThree, Schneelocke, Scray, Sengkang, Seraphimblade, Sewebster, ShaunMacPherson, Sheitan, ShelfSkewed, Shinkolobwe, Shisha-Tom, Shoessss, Shorvath, Shuipzv3, Sillybilly, Skatebiker, Sl, Smrgeog, Snezzy, Snori, Sokkor, SpLoT, Spitfire, Srich32977, Stemonitis, Stephen Hodge, Stephenpratt, SteveRamone, Stifynsemons, Stone, Suffusion of Yellow, Svante, TFOWR, Tagishsimon, Tetracube, The Anome, TheMoog, Thingg, Thumperward, Tiddly Tom, Tim Starling, Timtrent, Tomchiukc, Tpbradbury, Trovatore, TutterMouse, Twilsonb, Typingghadir, UnicornTapestry, Uthbrian, VMoreira, Varlaam, Velella, Versus22, Vsmith, Warut, Watch37264, Wctaiwan, Welte, Wendy Wendy, Widefox, William Avery, Wpeer1, Wtmitchell, Wyklety, Xhmikos, YOSF0113, Yekrats, Yilloslime, Yyy, Zundark, 448 anonymous edits
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 105
Image Sources, Licenses and Contributors
Symbol_support_vote.svg https://en.wikipedia.org/w/index.php?title=File:Symbol_support_vote.svg Public Domain Contributors: Anomie
Source: License:
Transparent.gif https://en.wikipedia.org/w/index.php?title=File:Transparent.gif Domain Contributors: Edokter
Source: Public
License:
Lithium_paraffin.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Lithium_paraffin.jpg License: Public Domain Contributors: Original uploader was Tomihahndorf at de.wikipedia
Na_(Sodium).jpg Source: https://en.wikipedia.org/w/index.php?title=File:Na_%28Sodium%29.jpg License: Creative Commons Attribution-Sharealike 3.0 Contributors: Original uploader was Dnn87 at en.wikipedia
Potassium-2.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Potassium2.jpg License: Creative Commons Attribution Contributors: unknown
Rb5.JPG Source: https://en.wikipedia.org/w/index.php?title=File:Rb5.JPG License: Creative Commons Attribution 3.0 Contributors: Dnn87
Cesium.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Cesium.jpg License: Creative Commons Attribution-Sharealike 3.0 Contributors: Dnn87 Contact email: Dnn87yahoo.dk
Alkalimetalle.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Alkalimetalle.jpg License: GNU Free Documentation License Contributors: Benutzer:Tomihahndorf
Cesium_water.theora.ogv https://en.wikipedia.org/w/index.php?title=File:Cesium_water.theora.ogv Creative Commons Attribution-Sharealike 3.0 Contributors: Philip Evans
magnify-clip.png Source: https://en.wikipedia.org/w/index.php?title=File:Magnifyclip.png License: Contributors: -
Nuvola_apps_kaboodle.svg Source: https://en.wikipedia.org/w/index.php?title=File:Nuvola_apps_kaboodle.svg License: Contributors: Cathy Richards, Pierpao, Tkgd2007, Waldir, 1 anonymous edits
Large_Sodium_Explosion.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Large_Sodium_Explosion.jpg License: Public Domain Contributors: Ajhalls
Potassium-graphite-xtal-3D-SF-A.png Source: https://en.wikipedia.org/w/index.php?title=File:Potassium-graphite-xtal-3D-SF-A.png License: Public Domain Contributors: Ben Mills
Potassium-graphite-xtal-3D-SF-B.png Source: https://en.wikipedia.org/w/index.php?title=File:Potassium-graphite-xtal-3D-SF-B.png License: Public Domain Contributors: Ben Mills
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Page 106
Lithium-nitride-xtal-CM-3D-polyhedra.png https://en.wikipedia.org/w/index.php?title=File:Lithium-nitride-xtal-CM-3Dpolyhedra.png License: Public Domain Contributors: Ben Mills
Source:
Rb9O2_cluster.png https://en.wikipedia.org/w/index.php?title=File:Rb9O2_cluster.png Domain Contributors: Axiosaurus
Source: Public
License:
Cs11O3_cluster.png Source: https://en.wikipedia.org/w/index.php?title=File:Cs11O3_cluster.png License: Public Domain Contributors: Axiosaurus
18-crown-6-potassium-3D-balls-A.png Source: https://en.wikipedia.org/w/index.php?title=File:18-crown-6-potassium-3D-balls-A.png License: Public Domain Contributors: Ben Mills
Cryptate_of_pottasium_cation.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Cryptate_of_pottasium_cation.jpg License: GNU Free Documentation License Contributors: en:User:M stone.
Methyllithium-tetramer-2-3D-balls.png Source: https://en.wikipedia.org/w/index.php?title=File:Methyllithium-tetramer-2-3D-balls.png License: Public Domain Contributors: Benjah-bmm27, Daniele Pugliesi
FlammenfärbungLi.png Source: https://en.wikipedia.org/w/index.php?title=File:Flammenf%C3%A4rbungLi.png License: Public Domain Contributors: Red devil 666, Saperaud
Flametest--Na.swn.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Flametest--Na.swn.jpg License: GNU Free Documentation License Contributors: User:Swn
FlammenfärbungK.png Source: https://en.wikipedia.org/w/index.php?title=File:Flammenf%C3%A4rbungK.png License: Public Domain Contributors: Red devil 666, Saperaud
Effective_Nuclear_Charge.svg Source: https://en.wikipedia.org/w/index.php?title=File:Effective_Nuclear_Charge.svg License: Creative Commons Zero Contributors: NikNaks
First_Ionization_Energy.svg https://en.wikipedia.org/w/index.php?title=File:First_Ionization_Energy.svg Creative Commons Attribution-Sharealike 3.0 Contributors: User:Sponk
Periodic_variation_of_Pauling_electronegativities.png Source: https://en.wikipedia.org/w/index.php?title=File:Periodic_variation_of_Pauling_electro negativities.png License: Creative Commons Attribution-Sharealike 2.5 Contributors: Physchim62
Atomic_radius_of_alkali_metals_and_alkaline_earth_metals.svg Source: https://en.wikipedia.org/w/index.php?title=File:Atomic_radius_of_alkali_metals_and_ alkaline_earth_metals.svg License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:DePiep
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Page 107
Electron_affinity_of_alkali_metals.svg Source: https://en.wikipedia.org/w/index.php?title=File:Electron_affinity_of_alkali_metals.svg License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:DePiep
Ionization_energy_of_alkali_metals_and_alkaline_earth_metals.svg Source: https://en.wikipedia.org/w/index.php?title=File:Ionization_energy_of_alkali_metals_a nd_alkaline_earth_metals.svg License: Creative Commons Attribution-Sharealike 3.0 Contributors: User:DePiep
Hydrogen_discharge_tube.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Hydrogen_discharge_tube.jpg License: Free Art License Contributors: Alchemist-hp (talk) ( www.psemendelejew.de)
Thallium_pieces_in_ampoule.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Thallium_pieces_in_ampoule.jpg License: Creative Commons Attribution-Sharealike 3.0 Contributors: W. Oelen
Wiki_letter_w.svg Source: https://en.wikipedia.org/w/index.php?title=File:Wiki_letter_w.svg License: GNU Free Documentation License Contributors: Anomie, Mifter
Wiki_letter_w_cropped.svg Source: https://en.wikipedia.org/w/index.php?title=File:Wiki_letter_w_cropped.svg License: Creative Commons Attribution-ShareAlike 3.0 Unported Contributors: Wiki_letter_w.svg: Jarkko Piiroinen derivative work: thumperward (talk)
Petalite.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Petalite.jpg License: Contributors: Eurico Zimbres
SodiumHydroxide.jpg Source: https://en.wikipedia.org/w/index.php?title=File:SodiumHydroxide.jpg License: Public Domain Contributors: Walkerma
Potassium_hydroxide.jpg https://en.wikipedia.org/w/index.php?title=File:Potassium_hydroxide.jpg Public Domain Contributors: User:Walkerma
Source: License:
Lepidolite-76774.jpg https://en.wikipedia.org/w/index.php?title=File:Lepidolite-76774.jpg Contributors: -
Source: License:
SolarSystemAbundances.png Source: https://en.wikipedia.org/w/index.php?title=File:SolarSystemAbundances.png License: Creative Commons Attribution-Sharealike 3.0 Contributors: Original uploader was 28bytes at en.wikipedia
Spodumene-usa59abg.jpg https://en.wikipedia.org/w/index.php?title=File:Spodumene-usa59abg.jpg Contributors: -
Lithium_mine,_Salar_del_Hombre_Muerto,_Argentina.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Lithium_mine%2C_Salar_del_Hombre _Muerto%2C_Argentina.jpg License: Public Domain Contributors: NASA Earth Observatory
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Page 108
Uyuni_landsat.JPG https://en.wikipedia.org/w/index.php?title=File:Uyuni_landsat.JPG Domain Contributors: Alfredobi, Juiced lemon, Prissantenbär
License:
Source: Public
Pichblende.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Pichblende.jpg License: Creative Commons Attribution-Sharealike 2.5 Contributors: Original uploader was Kgrr at en.wikipedia
FOCS-1.jpg Source: https://en.wikipedia.org/w/index.php?title=File:FOCS-1.jpg License: Public Domain Contributors: METAS
Lithium_carbonate.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Lithium_carbonate.jpg License: Public Domain Contributors: Benjah-bmm27, Jynto, Walkerma, 1 anonymous edits
GoiâniaRadiationsource.gif Source: https://en.wikipedia.org/w/index.php?title=File:Goi%C3%A2niaRadiationsource.gif License: GNU Free Documentation License Contributors: Anynobody
Symbol_book_class2.svg https://en.wikipedia.org/w/index.php?title=File:Symbol_book_class2.svg Creative Commons Attribution-Sharealike 2.5 Contributors: Lokal_Profil
Folder_Hexagonal_Icon.svg Source: https://en.wikipedia.org/w/index.php?title=File:Folder_Hexagonal_Icon.svg License: GNU Free Documentation License Contributors: Anomie, Mifter
Portal-puzzle.svg Source: https://en.wikipedia.org/w/index.php?title=File:Portalpuzzle.svg License: Public Domain Contributors: Anomie
Question_book-new.svg https://en.wikipedia.org/w/index.php?title=File:Question_book-new.svg GNU Free Documentation License Contributors: Tkgd2007
Sodium_peroxide_2grams.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Sodium_peroxide_2grams.jpg License: Creative Commons Attribution-Sharealike 3.0 Contributors: W. Oelen
Rubidium-oxide-xtal-3D-vdW-B.png Source: https://en.wikipedia.org/w/index.php?title=File:Rubidium-oxide-xtal-3D-vdW-B.png License: Public Domain Contributors: Ben Mills
Sodium-peroxide-unit-cell-3D-balls.png Source: https://en.wikipedia.org/w/index.php?title=File:Sodium-peroxide-unit-cell-3Dballs.png License: Public Domain Contributors: Ben Mills
Potassium-superoxide-unit-cell-3D-ionic.png Source: https://en.wikipedia.org/w/index.php?title=File:Potassium-superoxide-unit-cell-3Dionic.png License: Public Domain Contributors: Ben Mills
Halit-Kristalle.jpg Source: https://en.wikipedia.org/w/index.php?title=File:HalitKristalle.jpg License: GNU Free Documentation License Contributors: Original uploader was W.J.Pilsak at de.wikipedia
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Source: License:
Page 109
NaCl_polyhedra.png Source: https://en.wikipedia.org/w/index.php?title=File:NaCl_polyhedra.png License: Public Domain Contributors: Solid State
CsCl_polyhedra.png Source: https://en.wikipedia.org/w/index.php?title=File:CsCl_polyhedra.png License: Public Domain Contributors: Solid State
Nuvola_apps_edu_science.svg Source: https://en.wikipedia.org/w/index.php?title=File:Nuvola_apps_edu_science.svg License: Contributors: A32, Cwbm (commons), Humanist Geek, Ipatrol, JuTa, Mindmatrix, Origamiemensch, Pierpao, Rocket000, Shizhao, Wknight94, Ysangkok, 3 anonymous edits
Periodic_trends.svg Source: https://en.wikipedia.org/w/index.php?title=File:Periodic_trends.svg License: Creative Commons Zero Contributors: User:Mirek2
Text_document_with_red_question_mark.svg Source: https://en.wikipedia.org/w/index.php?title=File:Text_document_with_red_question_m ark.svg License: Contributors: User:Bdesham
Electron_binding_energy_vs_Z.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Electron_binding_energy_vs_Z.jpg License: GNU Free Documentation License Contributors: en:User:Bvcrist
Franck-Condon-diagram.png Source: https://en.wikipedia.org/w/index.php?title=File:Franck-Condon-diagram.png License: Creative Commons Attribution-ShareAlike 3.0 Unported Contributors: Mark M. Somoza
Electrostatic_Potential.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Electrostatic_Potential.jpg License: Creative Commons Zero Contributors: Original uploader was FrozenMan at en.wikipedia
Pauling_and_Mullikan_electronegativities.png Source: https://en.wikipedia.org/w/index.php?title=File:Pauling_and_Mullikan_electronegativit ies.png License: Creative Commons Attribution-Sharealike 2.5 Contributors: Physchim62
Pauling_and_Allred-Rochow_electronegativities.png Source: https://en.wikipedia.org/w/index.php?title=File:Pauling_and_AllredRochow_electronegativities.png License: Creative Commons Attribution-ShareAlike 3.0 Unported Contributors: Physchim62
Pauling_and_Sanderson_electronegativities.png Source: https://en.wikipedia.org/w/index.php?title=File:Pauling_and_Sanderson_electronegat ivities.png License: Creative Commons Attribution-Sharealike 2.5 Contributors: Physchim62
Pauling_and_Allen_electronegativities.png Source: https://en.wikipedia.org/w/index.php?title=File:Pauling_and_Allen_electronegativities .png License: Creative Commons Attribution-ShareAlike 3.0 Unported Contributors: Physchim62
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 110
Sn-119_isomer_shifts_in_hexahalostannates.png https://en.wikipedia.org/w/index.php?title=File:Sn119_isomer_shifts_in_hexahalostannates.png License: Creative Attribution-ShareAlike 3.0 Unported Contributors: Physchim62
Source: Commons
Commons-logo.svg https://en.wikipedia.org/w/index.php?title=File:Commons-logo.svg Contributors: Anomie
Carboxylic.Acids.Melting.&.Boiling.Points.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Carboxylic.Acids.Melting.%26.Boiling. Points.jpg License: Public Domain Contributors: Bender235, Kurgus, Rhadamante
Koflerbank.jpg https://en.wikipedia.org/w/index.php?title=File:Koflerbank.jpg Commons Attribution-Sharealike 3.0 Contributors: HBR
Source: License: logo
License:
Source: Creative
KruessM5k.jpg Source: https://en.wikipedia.org/w/index.php?title=File:KruessM5k.jpg License: Creative Commons Attribution-Sharealike 3.0 Germany Contributors: User:DerHexer
Melting_curve_of_water.jpg https://en.wikipedia.org/w/index.php?title=File:Melting_curve_of_water.jpg Public Domain Contributors: Belfer00, Daniele Pugliesi, Hnchan01, Koavf
Source: License:
Phase_change_-_en.svg https://en.wikipedia.org/w/index.php?title=File:Phase_change_-_en.svg Public Domain Contributors: F l a n k e r, penubag
Source: License:
Kochendes_wasser02.jpg https://en.wikipedia.org/w/index.php?title=File:Kochendes_wasser02.jpg GNU Free Documentation License Contributors: user:Markus Schweiss
Source: License:
Vapor_Pressure_Chart.png https://en.wikipedia.org/w/index.php?title=File:Vapor_Pressure_Chart.png Public Domain Contributors: Mbeychok
Source: License:
Binary_Boiling_Point_Diagram_new.svg Source: https://en.wikipedia.org/w/index.php?title=File:Binary_Boiling_Point_Diagram_new.s vg License: Creative Commons Attribution-Sharealike 2.5 Contributors: Binary_Boiling_Point_Diagram.PNG: H Padleckas derivative work: Michbich (talk)
Artsy_density_column.png https://en.wikipedia.org/w/index.php?title=File:Artsy_density_column.png Creative Commons Attribution 3.0 Contributors: User:Kelvinsong
Air_density_vs_temperature.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Air_density_vs_temperature.jpg License: GNU Free Documentation License Contributors: John M. Robinson
Speakerlink-new.svg Source: https://en.wikipedia.org/w/index.php?title=File:Speakerlink-new.svg License: Creative Commons Zero Contributors: User:Kelvinsong
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Page 111
Padlock-silver.svg Source: https://en.wikipedia.org/w/index.php?title=File:Padlocksilver.svg License: Contributors: This image file was created by AJ Ashton. Uploaded from English WP by User:Eleassar. Converted by User:AzaToth to a silver color.
Hydrogen_Spectra.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Hydrogen_Spectra.jpg License: Public Domain Contributors: Teravolt at en.wikipedia
Hexagonal.svg Source: https://en.wikipedia.org/w/index.php?title=File:Hexagonal.svg License: BSD Contributors: Original uploader was Danieljamesscott at en.wikipedia
Shuttle_Main_Engine_Test_Firing_cropped_edited_and_reduced.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Shuttle_Main_Engine_Test_Firing_cro pped_edited_and_reduced.jpg License: Public Domain Contributors: Avron, WTCA, 2 anonymous edits
Hydrogen_atom.svg Source: https://en.wikipedia.org/w/index.php?title=File:Hydrogen_atom.svg License: Public Domain Contributors: Bensaccount
Liquid_hydrogen_bubblechamber.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Liquid_hydrogen_bubblechamber.jpg License: Public Domain Contributors: Lamiot, Pieter Kuiper, Saperaud
Deuterium_discharge_tube.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Deuterium_discharge_tube.jpg License: Free Art License Contributors: Alchemist-hp (talk) ( www.psemendelejew.de)
Protium.svg Source: https://en.wikipedia.org/w/index.php?title=File:Protium.svg License: Public Domain Contributors: Blacklemon67 at en.wikipedia
Antoine-Laurent_Lavoisier_(by_Louis_Jean_Desire_Delaistre)RENEW.jpg Source: https://en.wikipedia.org/w/index.php?title=File:AntoineLaurent_Lavoisier_%28by_Louis_Jean_Desire_Delaistre%29RENEW.jpg License: Public Domain Contributors: Louis Jean Desire Delaistre, after Boilly
Emission_spectrum-H.svg https://en.wikipedia.org/w/index.php?title=File:Emission_spectrum-H.svg Creative Commons Zero Contributors: Merikanto, Adrignola
Nursery_of_New_Stars_-_GPN-2000-000972.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Nursery_of_New_Stars_-_GPN-2000000972.jpg License: Public Domain Contributors: NASA, Hui Yang University of Illinois ODNursery of New Stars
Office-book.svg Source: https://en.wikipedia.org/w/index.php?title=File:Officebook.svg License: Public Domain Contributors: Chris Down/Tango project
Crystal_energy.svg https://en.wikipedia.org/w/index.php?title=File:Crystal_energy.svg Lesser General Public License Contributors: Dhatfield
License:
Wiktionary-logo-en.svg https://en.wikipedia.org/w/index.php?title=File:Wiktionary-logo-en.svg
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Source: GNU
Source: License:
Page 112
Public Domain Contributors: Vectorized by , based on original logo tossed together by Brion Vibber
Wikibooks-logo.svg https://en.wikipedia.org/w/index.php?title=File:Wikibooks-logo.svg Contributors: User:Bastique, User:Ramac et al.
Source: License: logo
Wikiversity-logo.svg https://en.wikipedia.org/w/index.php?title=File:Wikiversity-logo.svg Contributors: Snorky (optimized and cleaned up by verdy_p)
Source: License: logo
Sound-icon.svg Source: https://en.wikipedia.org/w/index.php?title=File:Soundicon.svg License: GNU Lesser General Public License Contributors: Crystal SVG icon set
Cscr-featured.svg Source: https://en.wikipedia.org/w/index.php?title=File:Cscrfeatured.svg License: GNU Lesser General Public License Contributors: Anomie
Ammonium-2D.svg https://en.wikipedia.org/w/index.php?title=File:Ammonium-2D.svg Domain Contributors: Lukáš Mižoch
License:
Source: Public
Ammonium-3D-balls.png https://en.wikipedia.org/w/index.php?title=File:Ammonium-3D-balls.png Public Domain Contributors: Benjah-bmm27
Source: License:
Ammonium-3D-vdW.png https://en.wikipedia.org/w/index.php?title=File:Ammonium-3D-vdW.png Public Domain Contributors: Benjah-bmm27
Source: License:
Hydrochloric_acid_ammonia.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Hydrochloric_acid_ammonia.jpg License: Public Domain Contributors: User:Walkerma
Equilibrium.svg https://en.wikipedia.org/w/index.php?title=File:Equilibrium.svg Domain Contributors: L'Aquatique
License:
Source: Public
Bildung_Ammonium.svg https://en.wikipedia.org/w/index.php?title=File:Bildung_Ammonium.svg Public Domain Contributors: Yikrazuul
Dimethylammonium-formation-2D.png Source: https://en.wikipedia.org/w/index.php?title=File:Dimethylammonium-formation-2D.png License: Public Domain Contributors: Amada44, Benjah-bmm27, Edgar181
Hexagonal_close_packed.svg Source: https://en.wikipedia.org/w/index.php?title=File:Hexagonal_close_packed.svg License: Creative Commons Attribution-Sharealike 3.0 Contributors: DePiep, Torsch
Hutchinsonite-131710.jpg https://en.wikipedia.org/w/index.php?title=File:Hutchinsonite-131710.jpg Contributors: -
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Source: License:
Source: License:
Page 113
ď&#x201A;ˇ
Thallium_rod_corroded.jpg Source: https://en.wikipedia.org/w/index.php?title=File:Thallium_rod_corroded.jpg License: Creative Commons Attribution-ShareAlike 3.0 Unported Contributors: User:Dschwen
Dr. Pramod Kothari / Alkali Metals, ISBN/EAN13: 978-1-304-87524-2
Page 114