Peroxodisulfates

Peroxodisulfates are a group of chemical compounds with the general formula M2S2O8, where M is a cation, typically an alkali metal or ammonium. They are characterized by the presence of the peroxodisulfate anion, S2O8^2-. This anion contains a peroxide bond (-O-O-) linking two sulfate groups. Peroxodisulfates are strong oxidizing agents and are often encountered as white crystalline solids. They are soluble in water, and their solutions are acidic due to hydrolysis.

The most common peroxodisulfates are potassium peroxodisulfate (K2S2O8), sodium peroxodisulfate (Na2S2O8), and ammonium peroxodisulfate ((NH4)2S2O8). These compounds are typically synthesized by the electrolysis of sulfate solutions. During electrolysis, sulfate ions are oxidized at the anode to form the peroxodisulfate anion. The stability of peroxodisulfates in aqueous solution is moderate; they decompose over time, particularly when heated or in the presence of catalysts, releasing oxygen and sulfate ions.

Peroxodisulfates have several important industrial applications. They are widely used as initiators for the polymerization of various monomers, such as styrene, acrylonitrile, and vinyl chloride, in the production of plastics and synthetic rubbers. Their strong oxidizing properties also make them useful in cleaning agents, particularly for dental products, and in etching processes for printed circuit boards. Furthermore, they find use in textile bleaching and in the treatment of wastewater. Due to their oxidizing nature, appropriate safety precautions are necessary when handling peroxodisulfates, as they can be irritating to skin and eyes and can pose fire hazards when in contact with combustible materials.