Peroxymonosulfuric acid

Peroxymonosulfuric acid, also known as persulfuric acid, peroxysulfuric acid is the inorganic compound with the formula H₂SO₅. It is a white solid. It is a component of Caro's acid, which is a solution of peroxymonosulfuric acid in sulfuric acid containing small amounts of water.^[4] Peroxymonosulfuric acid is a very strong oxidant (E⁰ = +2.51 V).

Peroxymonosulfuric acid

Skeletal formula of peroxymonosulfuric acid
Ball and stick model of peroxymonosulfuric acid
Names
IUPAC names Peroxysulfuric acid Sulfuroperoxoic acid[1]
Systematic IUPAC name (Dioxidanido)hydroxidodioxidosulfur[1][2]
Other names Peroxosulfuric acid[1] Peroxomonosulfuric acid[citation needed] Persulfuric acid[citation needed] Caro's acid
Identifiers
CAS Number	7722-86-3 N
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:29286 Y
ChemSpider	2035480 Y
ECHA InfoCard	100.028.879
EC Number	231-766-6
Gmelin Reference	101039
PubChem CID	2754594
UNII	JC6U8R2UJ9 Y
UN number	1483
CompTox Dashboard (EPA)	DTXSID90884417
InChI InChI=1S/H2O5S/c1-5-6(2,3)4/h1H,(H,2,3,4) Y Key: FHHJDRFHHWUPDG-UHFFFAOYSA-N Y
SMILES OOS(O)(=O)=O [O].[O].OOSO
Properties
Chemical formula	H 2SO 5
Molar mass	114.078 g mol−1
Appearance	White crystals
Density	2.239 g cm−3
Melting point	45 °C
Acidity (pKa)	1, 9.3[3]
Conjugate base	Peroxomonosulfate
Structure
Coordination geometry	Tetrahedral at S
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	strong oxidizer
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Structure

In peroxymonosulfuric acid, the S(VI) center adopts its characteristic tetrahedral geometry; the connectivity is indicated by the formula HO–O–S(O)₂–OH. The S-O-H proton is more acidic.^[4]

History

The German chemist Heinrich Caro first reported investigations of mixtures of hydrogen peroxide and sulfuric acid.^[5]

Synthesis and production

One laboratory scale preparation of Caro's acid involves the combination of chlorosulfuric acid and hydrogen peroxide:^[6]

H₂O₂ + ClSO₂OH ⇌ H₂SO₅ + HCl

Patents include more than one reaction for preparation of Caro's acid, usually as an intermediate for the production of potassium monopersulfate (PMPS), a bleaching and oxidizing agent. One route employs the following reaction:^[7]

H₂O₂ + H₂SO₄ ⇌ H₂SO₅ + H₂O

This reaction is related to "piranha solution".

Uses in industry

H
₂SO
₅ and Caro's acid have been used for a variety of disinfectant and cleaning applications, e.g., swimming pool treatment and denture cleaning. It is used in gold mining to destroy the cyanide in the waste stream (tailings).

Alkali metal salts of H
₂SO
₅, especially oxone, are widely investigated.

Hazards

These peroxy acids can be explosive. Explosions have been reported at Brown University^[8] and Sun Oil. As with all strong oxidizing agents, peroxysulfuric acid is incompatible with organic compounds.

See also

• Peroxydisulfuric acid H
  ₂S
  ₂O
  ₈
• Peroxomonosulfate