Tellurium was discovered in gold-bearing ores by Müller von Reichenstein in 1782 and was given its name (after tellus, earth) by Klaproth in 1798. It is still only found in combination with other metal ores like gold and copper.
- Crystalline tellurium is a silvery metal with a typical metallic lustre.
- It is brittle and easily pulverised with only a hardness of 2.3 on Mohs’ scale.
- Amorphous tellurium is obtained by precipitation from solutions of tellurous acid H2TeO3 or telluric acid H2TeO4.
- Tellurium burns in air with a greenish flame to form TeO2.
- In the molten state it strongly corrodes metals such as iron and copper.
- Tellurium vapour consists mainly of Te2 molecules.
- The semiconductor properties of tellurium when alloyed with cadmium enable the use of tellurium in Cd-Te solar panels. In recent years the demand for this application has driven a surge in demand for tellurium
- Applications in alloys and steels of tellurium. Small additions of this metal, generally in the form of manganese telluride, improve the corrosion resistance and mechanical properties of lead. Tellurium also improves the machinability of stainless steels and copper.
- As bismuth telluride Bi2Te3 and lead telluride PbTe, it has found certain applications in the electronic and thermoelectric fields.
- Used as a catalyst in organic chemistry and, in the form of dithiocarbamate, in the vulcanisation of rubber.
- Se–Te–Sb and Te–Ge–Sb alloys are used in the manufacture of certain compact discs.
- Te–Se alloys are used in reprography and epitaxial Cd–Te used in x-ray detectors.
Tellurium is recovered from some anode slimes from the copper refining industry. Its dissipative use in applications like photovoltaics present recycling challenges although some tellurium is recovered from the production process for CdTe photovoltaics.