Common Polyatomic Ions

carbonate CO3 2-

bicarbonate HCO3 1-

phosphate PO4 3-

hydroxide OH 1-

peroxide O2 2-

cyanide CN 1-

sulfate SO4 2-

sulfite SO3 2-

nitrate NO3 1-

nitrite NO2 1-

ammonium NH4 +

acetate CH3COO 1-