Overview

Tellurium was discovered in 1782 by the Austrian mineralogist Franz-Joseph Muller von Reichenstein, in gold ores from Transylvania; it was named in 1798 by Martin Heinrich Klaproth, who confirmed it as a new element. The name comes from the Latin tellus, the Earth. Tellurium is a brittle, silvery-white metalloid, chemically akin to selenium and sulfur, used in alloys and in thermoelectric and solar-cell materials. Rare in the crust and recovered mainly from the refining of copper, tellurium is added to steel and copper to make them easier to machine, and its compounds are important in thermoelectric devices that turn heat into electricity and in cadmium-telluride thin-film solar panels.

Muller von Reichenstein was genuinely puzzled by his find, calling it metallum problematicum, the problem metal, and sending samples to the Swedish chemist Torbern Bergman for a definitive analysis; Bergman died before completing the work, and the element went unconfirmed and unnamed for a further sixteen years until Klaproth, working independently, verified it as a true new element in 1798 and gave it the name that stuck. The unusually long gap between discovery and confirmed naming makes tellurium one of the more protracted identification stories among the pre-twentieth-century elements.