Peroxydisulfate

The peroxydisulfate ion, S ₂O²⁻ ₈, is an oxyanion. It is commonly referred to as the persulfate ion or peroxodisulfate anions, but this term also refers to the peroxomonosulfate ion, SO²⁻ ₅. Approximately 500,000 tons of salts containing this anion are produced annually.