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| Names | |
|---|---|
| IUPAC names μ-peroxido-bis(hydroxidodioxidosulfur) peroxydisulfuric acid | |
| Other names Persulfuric acid, Peroxodisulfuric acid | |
| Identifiers | |
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| Properties | |
Chemical formula | H2O8S2 |
| Molar mass | 194.13 g·mol−1 |
| Appearance | Colourless solid |
| Melting point | 65 °C (149 °F; 338 K) (decomposes) |
| soluble | |
| Conjugate base | Peroxydisulfate |
| Related compounds | |
Other cations | Potassium persulfate Sodium persulfate Ammonium persulfate |
Related compounds | Peroxymonosulfuric acid Pyrosulfuric acid |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
Peroxydisulfuric acid is an inorganic compound with a chemical formula H2S2O8. Also called Marshall's acid after its inventor Professor Hugh Marshall,[1] it is a sulfur oxoacid.[2] In structural terms it can be written HO3SOOSO3H. It contains sulfur in its +6 oxidation state and a peroxide group. Its salts, commonly known as persulfates, are industrially important as powerful oxidizing agents.
Synthesis
The acid is prepared by the reaction of chlorosulfuric acid with hydrogen peroxide:[3]
- 2ClSO3H + H2O2 → H2S2O8 + 2 HCl
Another method is the electrolysis of moderately concentrated sulfuric acid (60-70%) with platinum electrodes at high current density and voltage:
- H2SO4 + H2O → H3O+ + HSO4− (dissociation of sulfuric acid)
- 2HSO4− → H2S2O8 + 2e− (E0 = +2.4V) (bisulfate oxidation)
- 2H2SO4 → H2S2O8 + H2 (overall reaction)
- 3H2O → O3 + 6H+ (ozone produced as a side product)
See also
References
- ^ Senning, Alexander (2006-10-30). Elsevier's Dictionary of Chemoetymology: The Whys and Whences of Chemical Nomenclature and Terminology. ISBN 9780080488813.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- ^ Harald Jakob, Stefan Leininger, Thomas Lehmann, Sylvia Jacobi, Sven Gutewort. "Peroxo Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_177.pub2.