Peroxydisulfuric acid

Peroxydisulfuric acid
Names
	IUPAC names μ-peroxido-bis(hydroxidodioxidosulfur); peroxydisulfuric acid
	Other names Persulfuric acid, Peroxodisulfuric acid
Identifiers
CAS Number	13445-49-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:29268 ;
ChemSpider	22822 ;
PubChem CID	24413;
UNII	2RQ1860626 ;
CompTox Dashboard (EPA)	DTXSID00894926 ;
	InChI InChI=1S/H2O8S2/c1-9(2,3)7-8-10(4,5)6/h(H,1,2,3)(H,4,5,6) Key: JRKICGRDRMAZLK-UHFFFAOYSA-N ; InChI=1/H2O8S2/c1-9(2,3)7-8-10(4,5)6/h(H,1,2,3)(H,4,5,6)/f/h1,4H; InChI=1/H2O8S2/c1-9(2,3)7-8-10(4,5)6/h(H,1,2,3)(H,4,5,6) Key: JRKICGRDRMAZLK-UHFFFAOYAS;
	SMILES O=S(=O)(OOS(=O)(=O)O)O;
Properties
Chemical formula	H2O8S2
Molar mass	194.13 g·mol−1
Appearance	Colourless solid
Melting point	65 °C (149 °F; 338 K) (decomposes)
Solubility in water	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). verify (what is ?) Infobox references

Peroxydisulfuric acid is an inorganic compound with a chemical formula (HO₃SO)₂. Also called Marshall's acid after Professor Hugh Marshall, who discovered it in 1891.^[1]

Structure and bonding

This oxoacid features sulfur in its +6 oxidation state and a peroxide group. Sulfur adopts the usual tetrahedral geometry.^[2]

Synthesis

The acid is prepared by the reaction of chlorosulfuric acid with hydrogen peroxide:^[3]

2 ClSO₃H + 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)

2 HSO₄⁻ → H₂S₂O₈ + 2 e⁻ (E₀ = +2.4V) (bisulfate oxidation)

2 H₂SO₄ → H₂S₂O₈ + H₂ (overall reaction)

3 H₂O → O₃ + 6 H⁺ (ozone produced as a side product)

Uses

Peroxydisulfuric acid is a precursor to several salts including sodium peroxydisulfate, potassium peroxydisulfate, and ammonium peroxydisulfate. These salts are used to initiate the polymerization of acrylonitrile, styrene, and related monomers. This application exploits the tendency of the peroxydisulfate anion to undergo homolysis to produce radicals. They are also used as cleaning of circuit boards.^[3]

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.
^ ^a ^b 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. ISBN 978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

[1] Senning, Alexander (2006-10-30). Elsevier's Dictionary of Chemoetymology: The Whys and Whences of Chemical Nomenclature and Terminology. ISBN 9780080488813.

[2] Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.

[Ullmann-3] 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. ISBN 978-3527306732.{{cite encyclopedia}}: CS1 maint: multiple names: authors list (link)

[1]

[2]

[3]

Structure and bonding

Synthesis

Uses

See also

References