Product Code Database
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 regarding reaction chemistry has been obtained in studies involving paratellurite, α-TeO2.W.R.McWhinnie (1995) Tellurium - Inorganic chemistry Encyclopedia of Inorganic Chemistry Ed. R. Bruce King (1994) John Wiley & Sons
An alternative preparation is to dehydrate tellurous acid, H2TeO3, or to thermally decompose basic tellurium nitrate, Te2O4·HNO3, above 400 °C.
The tellurite ion is kinetically inert, but TeO2 equivalents will oxidize thioates in acid to the diacyl disulfide.
melts at 732.6 °C, forming a red liquid.(2025). 9780123526519, Academic Press. ISBN 9780123526519The structure of the liquid, as well as the glass which can be formed from it with sufficiently rapid cooling, are also based on approximately four coordinate Te. However, compared to the crystalline forms, the liquid and glass appear to incorporate short-range disorder (a variety of coordination geometries) which marks TeO2 glass as distinct from the canonical single-oxide glass-formers such as SiO2, which share the same short-range order with their parent liquids.
Tellurium dioxide is also a reluctant glass former, it will form a glass under suitable cooling conditions, or with additions of a small molar fraction of a second compound such as an oxide or halide. TeO2 glasses have high refractive indices and transmit into the mid-infrared part of the electromagnetic spectrum, therefore they are of technological interest for optical waveguides. Tellurite glasses have also been shown to exhibit Raman gain up to 30 times that of silica, useful in optical fibre amplification.
Exposure to tellurium compounds produces a garlic-like odour on the breath, caused by the formation of diethyl telluride.
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