With hydrogen and with some metals it forms tellurides. Tellurium and its compounds are probably poisonous. Tellurium is recovered as a byproduct of the electrolytic refining of blister copper. It is used as an additive to steel and is often alloyed with aluminum, copper, lead, or tin. It is used in vulcanizing rubber, as a coloring agent in glass and ceramics, and in catalysts for petroleum cracking.
Tellurium is a semiconductor material and is slightly photosensitive.
It is used with bismuth in thermoelectric devices. Tellurium was discovered in 1782 by Franz Muller von Reichenstein. It was named by M. H. Klaproth, who isolated it in 1798. The Columbia Encyclopedia, Sixth Edition.