Se - Selenium

Selenium

Selenium

Atomic Number:	34
Atomic Weight:	78.96
Element Type:	Non-Metal
Crystal Structure:	Hexagonal
Melting Point:	221.0°C = 429.8°F = 494.15 K
Boiling Point:	685.0°C = 1265.0°F = 958.15 K
Critical Temp:	1493.0°C = 2719.4°F = 1766.15 K
Atomic Radius:	1.22 Å (Å = Angstrom = 10^-10 m)
Covalent Radius:	1.16 Å
Electronegativity:	2.55

History

(Gr. Selene, moon) Discovered by Berzelius in 1817, who found it associated withtellurium, named for the earth.

Sources

'The mathematician's patterns, like the painter's or the poets, must be beautiful; the ideas, like the colours or the words, must fit together in a harmonious way. Beauty is the first test: there is no permanent place in the world for ugly mathematics.'

Godfrey Hardy
(1877-1947)