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Thiosulfuric acid

Thiosulfuric acid
IUPAC name sulfurothioic O-acid
Other names thiosulfuric acid dihydroxidooxidosulfidosulfur
CAS number 7772-98-7
Molecular formula H2S2O3
Molar mass 114.14408
Solubility in water decomposes
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)

Infobox disclaimer and references

Thiosulfuric acid is a sulfur oxoacid. The acid cannot be made by acidifying thiosulfate salts as the acid readily decomposes in water. The decomposition products can include, depending on the exact reaction conditions, sulfur, sulfur dioxide, hydrogen sulfide, polysulfanes, sulfuric acid and polythionates. Anhydrous methods of producing the acid include:

(in diethyl ether at -78°C )
H2S + SO3 → H2S2O3·nEt2O
Na2S2O3+2HCl→ 2NaCl + H2S2O3·2Et2O

The anhydrous acid decomposes below 0°C :

H2S2O3→ H2S + SO3

There is an isomeric form, a white crystalline adduct, H2S.SO3 which can be prepared at low temperature.

See also


Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4. 

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Thiosulfuric_acid". A list of authors is available in Wikipedia.
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