Common Polyatomic Ions

ChemistryUpdated October 25, 2026

List of common polyatomic ion formulas and charges.

Common Polyatomic Ions

Ammonium: NH4+

Hydronium: H3O+

Acetate: C2H3O2-

Hydroxide: OH-

Chlorate: ClO3-

Nitrate: NO3-

Carbonate: CO3(2-)

Chromate: CrO4(2-)

Sulfate: SO4(2-)

Phosphate: PO4(3-)