38 Common Polyatomic Ions John Moore, Jia Zhou, and Etienne Garand Polyatomic Ions (common) 0 1 Cations NaN NH4+ Ammonium Hg22+ Mercury(I) Anions (1-) NaN OH− Hydroxide HSO4− Hydrogen sulfate CH3COO− Acetate ClO− Hypochlorite ClO2− Chlorite ClO3− Chlorate ClO4− Perchlorate NO2− Nitrite NO3− Nitrate MnO4− Permanganate H2PO4− Dihydrogen phosphate CN− Cyanide HCO3− Hydrogen carbonate SCN− Thiocyanate Anions (2-) NaN O22− Peroxide SO32− Sulfite SO42− Sulfate S2O32− Thiosulfate Cr2O72− Dichromate CrO42− Chromate CO32− Carbonate HPO42− Monohydrogen phosphate C2O42− Oxalate Anions (3-) NaN PO43− Phosphate AsO43− Arsenate