Tellurite

Tellurite is a oxyanion of tellurium with the formula Template:Chem. It is the ion of tellurous acid, and is chemically related to tellurium dioxide (Template:Chem), whose mineral appearance also bears the name tellurite. Tellurites are typically colorless or white salts, which in some ways are comparable to sulfite.

Structure and reactions

File:Na2TeO3.png

Crystal structure of sodium tellurite, highlighting the pyramidal structure of the anion.

Tellurite dianion is pyramidal, like selenite and sulfite. The anion has C_3v symmetry.

Tellurites can be reduced to elemental tellurium by electrolysis or a strong reducing agent. When fused with nitrate salts, tellurite salts oxidize to tellurates (Template:Chem).

Upon acidification of aqueous solutions of tellurite salts, solid hydrated tellurium dioxide (TeO₂) precipitates. This reaction allows the separation of tellurium from selenium since selenous acid remains soluble at low pH. The intermediate in the protonation occurs at oxygen to give [TeO₂(OH)]⁻.

Compounds

• Sodium tellurite
• Potassium tellurite (K₂TeO₃) is used together with agar as part of a selective medium for growth of some bacteria (Clauberg medium). Corynebacteria and some other species reduce Template:Chem to elemental Te, which stains the bacteria black.

Biological activity

Tellurite (TeO₃²⁻) is a highly toxic oxyanion of tellurium with notable biological activity, particularly due to its toxic effects on various organisms, including bacteria, plants, and humans. The lack of mitochondrial proteins MRPL44, NAM9 (MNA6) and GEP3 (MTG3) in yeast is associated with resistance to tellurite.

See also

• List of tellurites

Further reading

• M. R. Masson, H. D. Lutz and B. Engelen (eds.) "Sulfites, Selenites and Tellurites", Pergamon Press, Oxford, 1986.