The tellurite
ion
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 ...
is . A tellurite (compound), for example
sodium tellurite, is a compound that contains this ion. They are typically colorless or white salts, which in some ways are comparable to
sulfite.
A mineral with the formula TeO
2 is called tellurite.
Structure and reactions
![Na2TeO3](https://upload.wikimedia.org/wikipedia/commons/7/7f/Na2TeO3.png)
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
In chemistry, a reducing agent (also known as a reductant, reducer, or electron donor) is a chemical species that "donates" an electron to an (called the , , , or ).
Examples of substances that are commonly reducing agents include the Earth me ...
. When fused with nitrate salts, tellurite salts oxidize to tellurates ().
Upon acidification of aqueous solutions of tellurite salts, solid hydrated
tellurium dioxide
Tellurium dioxide (TeO2) is a solid oxide of tellurium. It is encountered in two different forms, the yellow orthorhombic mineral tellurite, β-TeO2, and the synthetic, colourless tetragonal (paratellurite), α-TeO2. Most of the information regard ...
(TeO
2) precipitates. This reaction allows the separation of tellurium from selenium since
selenous acid
Selenous acid (or selenious acid) is the chemical compound with the formula . Structurally, it is more accurately described by . It is the principal oxoacid of selenium; the other being selenic acid.
Formation and properties
Selenous acid is a ...
remains soluble at low pH. The intermediate in the protonation occurs at oxygen to give
2(OH)">eO2(OH)sup>−.
Uses
Potassium tellurite (K
2TeO
3) is used together with agar as part of a selective medium for growth of some bacteria (Clauberg medium).
Corynebacteria
''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name (''coryneform'' means "club-shape ...
and some other species reduce to elemental Te, which stains the bacteria black.
See also
*
List of tellurites
References
{{Reflist
Further reading
*M. R. Masson, H. D. Lutz and B. Engelen (eds.) "Sulfites, Selenites and Tellurites", Pergamon Press, Oxford, 1986.
Oxyanions
Microbiological media ingredients
Tellurites