Thallium

Thallium (Th)

Atomic Number: 81
Atomic Weight: 204.37
Melting Point: 303.5
Boiling Point: 1457
Specific Gravity: 11.85
Valence(s): 1 or 3
Thallium was isolated by Crookes and Lamy in 1862. Thallium is shiny, but turns dull when exposed to air. It is found in the minerals crooksite and lorandite. Since it is toxic but odourless, thallium sulfate is used in rodent and ant poison. Other thallium compounds have been used to produce glasses with a high refractive index or a low melting point. [LM] {RW}