Te

Tellurium (symbol Te, atomic number 52) is a brittle, silvery-white metalloid in the chalcogen group. It possesses semiconducting properties and is used in electronics and thermoelectric devices. Tellurium was identified in the late 18th century from telluride minerals; the name derives from the Latin tellus, “earth.”

Physically, tellurium has a layered crystalline structure and is relatively resistant at room temperature. It forms compounds in several oxidation states, most commonly +4 and +6. The oxide TeO2 is a common compound, and tellurite and tellurate species occur in solutions. Tellurium can form alloys with copper, silver, and other metals to improve machinability and grain structure. In industry, tellurium compounds are used in infrared detectors and in thermoelectric materials, including systems based on tellurides.

Occurrence and production: Tellurium is relatively rare in the Earth's crust and is typically recovered as a byproduct of refining copper, lead, gold, and silver ores, or from telluride-bearing minerals such as calaverite (AuTe2) and sylvanite (AgAuTe4). Global production is therefore linked to the mining and refining of base and precious metal ores.

Applications: It is used as an alloying agent to improve machinability in steel and copper. Tellurium compounds are employed in infrared optics, photovoltaics, and thermoelectric devices. It also finds use in pigments for ceramics and glass.

Safety: Tellurium and many of its compounds can be hazardous if mishandled; inhalation of dust or fumes should be avoided and normal industrial hygiene practices followed. Chronic exposure and certain organotellurium compounds may pose risks, so proper handling and disposal are important.