Selenium Properties, Molecular Formula, Applications - WorldOfChemicals

Selenium Properties




Selenium is a nonmetal, chemically related to sulfur and tellurium, and rarely occurs in its elemental state in nature. It conducts electricity better in the light than in the dark, and is used in photocells. It is found in economic quantities in sulfide ores such as pyrite, partially replacing the sulfur in the ore matrix. The chief commercial uses for selenium today are in glass making and in chemicals and pigments. Uses in electronics, once important, have been supplanted by silicon semiconductor devices. It is used widely in vitamin preparations and other dietary supplements, in small doses. Some livestock feeds are fortified with selenium as well. It is used in the toning of photographic prints. Selenium is a catalyst in many chemical reactions and is widely used in various industrial and laboratory syntheses, especially organoselenium chemistry. It is also widely used in structure determination of proteins and nucleic acids by X-ray crystallography.

Chemical Properties

Appearance Dark grey to dark red powder or crystals
Atomic Number 34
Atomic Weight 78.96 g/mol
Block p
Boiling Point 685 °C
CAS Number 7782-49-2
Class 6.1
Crystal Structure Hexagonal
Density 4.81 g/cm3
EINECS Number 231-957-4
Electron Configuration 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p4
Group 16
Ionization Energy 941 KJ/mol
Melting Point 221 °C
NFPA 704 H-2,F-1,R-0,C-NA
Oxidation State 6,4,2,1,-2
PG 3
Period 4
RTECS Number VS7700000
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