Tellium

Tellium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid that looks similar to tin. Tellium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in native form as elemental crystals. Tellium is also found in the minerals calaverite, sylvanite, and tellurite. Tellurium is primarily used in alloys, most notably with steel, to improve machinability. It is also used in certain semiconductor applications and as a catalyst in petroleum refining. Tellium has several isotopes, the most stable of which is tellurium-128. Tellurium is not known to have any biological role and is considered toxic in large amounts. It was discovered in 1782 by Franz Joseph Müller von Reichenstein, who identified it as a new element from a mineral he had received from a mine in Transylvania. The name tellurium comes from the Latin word "tellus," meaning "earth," reflecting the element's association with the mineral tellurite.