Polyatomic Ions Ion	Formula
Ammonium	NH4^+
Hydronium	H3O^+
Acetate	C2H3O2^-
Perchlorate	ClO4^-
Chlorate	ClO3^-
Chlorite	ClO2^-
Hypochlorite	ClO^-
Cyanide	CN^-
Carbonate	CO3^2-
Hydrogen carbonate	HCO3^-
Peroxide	O2^2-
Phosphate	PO4^3-
Hydrogen phosphate	HPO4^2-
Dihydrogen phosphate	H2PO4^-
Sulfate	SO4^2-
Sulfite	SO3^2-
Hydrogen sulfite	HSO3^-
Nitrate	NO3^-
Nitrite	NO2^-
Permanganate	MnO4^-
Thiocyanate	SCN^-
Chromate	CrO4^2-
Dichromate	Cr2O7^2-
Hydroxide	OH^-