Persulfate

The term persulfate refers to ions or compounds with more oxygen than normal sulfates.

These do not have sulfur in a different oxidation state; rather, they contain peroxide units, where two oxygens take the place of one in a normal sulfate; the oxygen atoms are in oxidation state −1.

The main forms are peroxomonosulfates and peroxodisulfates.

Ions

• Peroxomonosulfate (or Peroxymonosulfate) ion, SO₅²⁻
• Peroxodisulfate (or Peroxydisulfate) ion, S₂O₈²⁻

Acids

• Peroxymonosulfuric acid (peuric acid)(Caro's Acid), H₂SO₅
• Peroxydisulfuric acid, H₂S₂O₈

Example salts

• Sodium peroxomonosulfate, Na₂SO₅
• Potassium peroxymonosulfate, KHSO₅
• Sodium peroxodisulfate, Na₂S₂O₈
• Ammonium peroxydisulfate, (NH₄)₂S₂O₈