The telluride ion is the

anion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by conve ...

Te²⁻ and its derivatives. It is analogous to the other chalcogenide anions, the lighter O²⁻, S²⁻, and Se²⁻, and the heavier Po²⁻. In principle, Te²⁻ is formed by the two-e⁻ reduction of

tellurium Tellurium is a chemical element with the symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionall ...

. The redox potential is −1.14 V. :Te(s) + 2 e⁻ ↔ Te²⁻ Although solutions of the telluride dianion have not been reported, soluble salts of bitelluride (TeH⁻) are known.

Organic tellurides

''Tellurides'' also describe a class of organotellurium compounds formally derived from Te²⁻. An illustrative member is dimethyl telluride, which results from the

methylation In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These ...

of telluride salts: :2 CH₃I + Na₂Te → (CH₃)₂Te + 2 NaI Dimethyl telluride is formed by the body when tellurium is ingested. Such compounds are often called telluroethers because they are structurally related to

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again ...

s with tellurium replacing oxygen, although the length of the C–Te bond is much longer than a C–O bond. C–Te–C angles tend to be closer to 90°.

Inorganic tellurides

Many metal tellurides are known, including some

telluride mineral A telluride mineral is a mineral that has the telluride anion as a main component. Tellurides are similar to sulfides and are grouped with them in both the Dana and Strunz mineral classification systems.http://webmineral.com/strunz/II.shtml Webm ...

s. These include natural gold tellurides, like calaverite and krennerite (AuTe₂), and

sylvanite Sylvanite or silver gold telluride, chemical formula , is the most common telluride of gold. Properties The gold:silver ratio varies from 3:1 to 1:1. It is a metallic mineral with a color that ranges from a steely gray to almost white. It is c ...

(AgAuTe₄). They are minor ores of gold, although they comprise the major naturally occurring compounds of gold. (A few other natural compounds of gold, such as the bismuthide maldonite (Au₂Bi) and antimonide aurostibite (AuSb₂), are known). Although the bonding in such materials is often fairly covalent, they are described casually as salts of Te²⁻. Using this approach, Ag₂Te is derived from Ag⁺ and Te²⁻. Catenated Te anions are known in the form of the polytellurides. They arise by the reaction of telluride dianion with elemental Te: :Te^2- + n Te → Te_n+1^2-

Applications

Tellurides have no large scale applications. Cadmium telluride has attractive

photovoltaic Photovoltaics (PV) is the conversion of light into electricity using semiconducting materials that exhibit the photovoltaic effect, a phenomenon studied in physics, photochemistry, and electrochemistry. The photovoltaic effect is commercially ...

properties. Both bismuth telluride and lead telluride are exceptional thermoelectric materials. Some of these thermoelectric materials have been commercialized.

References

Anions {{Inorganic-compound-stub