Peroxydisulfuric Acid

Peroxydisulfuric acid is a sulfur oxoacid with the chemical formula H₂S₂O₈. It is also called Marshall's acid. In structural terms it can be written HO₃SOOSO₃H. It contains sulfur in its +6 oxidation state, but it also contains a peroxide group, which is why it appears to be in a higher oxidation state than sulfates. Its salts, commonly known as persulfates, are industrially important but the acid itself is not. The salts contain the peroxydisulfate ion. They are powerful oxidizing agents.