Peroxydisulfuric acid
Peroxydisulfuric acid is the inorganic compound with the chemical formula H2S2O8. Also called Marshall's acid, it is sulfur oxoacid. In structural terms it can be written HO3SOOSO3H. It contains sulfur in its +6 oxidation state and a peroxide group. Its salts, commonly known as persulfates, are industrially important as powerful oxidizing agents.