Peroxydisulfate

A ball-and-stick model of the peroxodisulfate anion

The structure of the peroxodisulfate anion

The peroxydisulfate ion, S₂O₈²⁻, is a oxyanion. It is commonly referred to as the persulfate ion, but this term also refers to the peroxomonosulfate ion, SO₅²⁻. 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.^[1]

Applications

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

[O₃SO-OSO₃]²⁻ 2 [SO₄]•⁻

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

• Elbs persulfate oxidation
• Oxidation of Ag⁺ to Ag²⁺

References

1. ↑ Harald Jakob, Stefan Leininger, Thomas Lehmann, Sylvia Jacobi, Sven Gutewort (2005), "Peroxo Compounds, Inorganic", Ullmann's Encyclopedia of Industrial Chemistry, Weinheim: Wiley-VCH, doi:10.1002/14356007.a19_177.pub2