telluuri

Tellurium (Te, atomic number 52) is a brittle, silvery-white metalloid in the chalcogen family. It occurs in the Earth's crust only in trace amounts and is usually obtained as a byproduct of copper and gold refining. Tellurium compounds are often found in telluride minerals such as calaverite (AuTe2) and sylvanite ((Ag,Au)Te4).

Properties: Tellurium is a relatively rare element with semiconducting properties and photoconductivity. It has a melting point of about 722–727°C and a boiling point around 1,023°C. In pure form it is hard to work with, being brittle and having low hardness; its compounds span oxidation states from −2 to +6.

Uses: Elemental tellurium is used in small amounts to improve alloy machinability and to deaerate iron and steel. It is also a key component in many thermoelectric materials and is widely used in cadmium telluride (CdTe) solar cells and infrared detectors. Tellurides of gold, silver, and other metals are important in electronics and specialty alloys.

History: Tellurium was discovered in 1782 by Franz-Joseph Müller von Reichenstein and was independently described by Martin Heinrich Klaproth, who gave it the name tellurium, from the Latin tellus, “earth.”

Safety: Tellurium and many of its compounds are toxic if ingested or inhaled. Chronic exposure can cause adverse health effects; proper handling and ventilation are recommended.