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.
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:
In addition to its major commercial applications, peroxydisulfate participates in reactions of interest in the laboratory:
- Elbs persulfate oxidation
- Oxidation of Ag+ to Ag2+