Disulfuric acid
From Wikipedia, the free encyclopedia
| Disulfuric acid | |
|---|---|
 |
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| IUPAC name | Disulfuric acid |
| Other names | Pyrosulfuric acid |
| Identifiers | |
| CAS number | [7783-05-3] |
| SMILES | OS(=O)(=O)OS(=O)(=O)O |
| Properties | |
| Molecular formula | H2S2O7 |
| Molar mass | 178.14168 |
| Melting point |
36°C |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Disulfuric acid is a sulfur oxoacid. It is a major constituent of fuming sulfuric acid, oleum, and this is how most chemists encounter it. It is also a minor constituent of liquid anhydrous sulfuric acid due to the equilibria:
- H2SO4 ⇌ H2O + SO3
- SO3 + H2SO4 ⇌ H2S2O7
The acid is prepared by reacting excess SO3 with sulfuric acid:
- H2SO4 + SO3 → H2S2O7
Disulfuric acid is a strong acid and protonates sulfuric acid in the (anhydrous) sulfuric acid solvent system. There are salts of disulfuric acid, commonly called pyrosulfates, e.g. potassium pyrosulfate.
There are other related acids with the general formula H20.(SO3)x e.g. H2S4O13(melting point 4°C).
[edit] See also
[edit] Footnotes
Greenwood, N. N.; Earnshaw, A. (1997). Chemistry of the Elements, 2nd Edition, Oxford:Butterworth-Heinemann. ISBN 0-7506-3365-4.
