Thiosulfuric acid

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

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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

• sulfur oxoacids for other sulfur oxoacids

Footnotes

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