Peroxydisulfate

Names
Other names Peroxodisulfate Persulfate[1]
Identifiers
CAS Number	15092-81-6
3D model (JSmol)	Interactive image
ChEBI	CHEBI:29267
ChemSpider	97014
PubChem CID	107879
UNII	1SQ1481FEQ
InChI InChI=1S/H2O8S2/c1-9(2,3)7-8-10(4,5)6/h(H,1,2,3)(H,4,5,6)/p-2 Key: JRKICGRDRMAZLK-UHFFFAOYSA-L
SMILES [O-]S(=O)(=O)OOS([O-])(=O)=O
Properties
Chemical formula	O8S2−2
Molar mass	192.11 g·mol−1
Conjugate acid	Peroxydisulfuric acid
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

The peroxydisulfate ion, S
₂O²⁻
₈, is an oxyanion, the anion of peroxydisulfuric acid. It is commonly referred to as persulfate, but this term also refers to the peroxomonosulfate ion, SO²⁻
₅. It is also called peroxodisulfate.^[2] Approximately 500,000 tons of salts containing this anion are produced annually. Important salts include sodium persulfate (Na₂S₂O₈), potassium persulfate (K₂S₂O₈), and ammonium persulfate ((NH₄)₂S₂O₈). These salts are colourless, water-soluble solids that are strong oxidants.^[3]

Salts of peroxydisulfate are mainly used to initiate the polymerization of various alkenes, including styrene, acrylonitrile, and fluoroalkenes. Polymerization is initiated by the homolysis of the peroxydisulfate:

[O₃SO–OSO₃]²⁻ ⇌ 2 [SO₄]^•−

Moreover, sodium peroxydisulfate can be used for soil and groundwater remediation, water and wastewater treatment, and etching of copper on circuit boards.^[4][2]

It has also been used to produce hair lighteners and bleaches, medical drugs, cellophane, rubber, soaps, detergents, adhesive papers, dyes for textiles, and in photography.^[2]

In addition to its major commercial applications, peroxydisulfate participates in reactions of interest in the laboratory:

• Elbs persulfate oxidation
• Oxidation of Ag⁺ to Ag²⁺, such as the preparation of tetrakis(pyridine)silver(II) peroxydisulfate

Peroxydisulfate is a centrosymmetric anion. The O-O distance is 1.48 Å. The sulfur centers are tetrahedral.^[5]