| IUPAC name
| Other names
|Molar mass||194.143 g/mol|
|Melting point||65 °C (149 °F; 338 K) (decomposes)|
|Solubility|| Reacts with amines|
Soluble in alcohols (reacts)
Insoluble in ether
|Safety data sheet||None|
| Sulfuric acid|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Peroxydisulfuric acid or Marshall's acid, is a chemical compound, a strong oxoacid with the chemical formula H2S2O8. The free acid is not used in chemistry, but it's salts are more often encountered.
Peroxydisulfuric acid will react violently with many organic compounds.
- H2S2O8 + 2 H2O → 2 H2SO4 + H2O2
Partial hydrolysis of peroxydisulfuric acid produces peroxymonosulfuric acid and sulfuric acid.
- H2S2O8 + H2O → H2SO5 + H2SO4
Peroxydisulfuric acid is a hygroscopic colorless solid, that is soluble in water.
The pure acid is not sold, instead its salts are more readily available.
- 2 ClSO3H + H2O2 → H2S2O8 + 2 HCl
The solid form is extremely difficult to obtain, and it's more often encountered as solution.
- Make persulfate salts
Peroxydisulfuric acid is highly corrosive and may explode in contact with organic substances.
Peroxydisulfuric acid is not very stable, but at least one source claims it can be kept relative stable at low temperatures, for up to 8 weeks.. Aqueous solutions of this acid are more stable at 0-17 °C.
Peroxoacids should not be stored, as they will react violently with anything organic (dust, particulates, hair strands, etc.).
Should be dissolved in water and neutralized with a reducing agent and a base.
- D'Ans, J.; Zeitschrift fuer Elektrochemie; vol. 17; (1911); p. 849 - 851
- Elbs, K.; Schoenherr, O.; Zeitschrift fuer Elektrochemie; vol. 1; (1894); p. 468 - 472,