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History and Production
From Greek, anti monos, meaning a metal not found alone. Antimony compound has been used since ancient times. It was known as a metal at least since the beginning of the 17th century. It is extracted from the sulfide by roasting to the oxide. It is then reduced to the metal by heating charcoal with salt (alkali metal sulfate) as flux. Higher grade of antimony ores may be treated with scrap iron to remove the sulfide.
Very pure metal can be obtained by means of electrolysis, followed by zone-refining. It is used in semiconductor industry (such as AlSb, GaSb and InSb) for making infrared detectors, diode and Hall-effect devices. The metal is also used for making alloys with lead. Its compounds such as oxides and sulfides
are used in flame-proofing materials, paints, glass and pottery.
Physical Data
It is bluish white and has a metallic luster. It is very brittle and flaky in nature. It consists of about 0.2 ppm of the crustal rocks and is known to exist in more 100 minerals. It mainly exists in stibnite (Sb2S3), but also in valentinite (Sb2O3) and cervanite (Sb2O4).
Interatomic distance: 290 pm
Melting point: 630.63°C
Boiling point: 1587°C
Thermal conductivity/Wm-1K-1: 24.3 (27°C)
Density/kgm-3: 6691 (20°C), 6483 (m.p.)
Standard Thermodynamic Data (atomic gas)
Enthalpy of formation: 262.3 kJ/mol
Gibbs free energy of formation: 222.1 kJ/mol
Entropy: 180.3 J/mol K
Heat capacity: 20.8 J/mol K
Electronic data
Electronic configuration: [Kr] 4d10 5s2 5p3
Term symbol: 4S3/2
Electron affinity: 100.9237 kJ/mol Electronegativity (Pauline): 2.05
Ionization energy (first, second, third): 830.585, 1594.95, 2441.08 kJ/mol
Chemical properties
Antimony is not attacked by hydrochloric or dilute sulfuric acids. However, with moderately concentrated nitric acid, it is oxidised to give antimony(III) oxide, Sb4O6.
With higher concentrations, the (v) oxide, Sb2O5, is formed.
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