Common Polyatomic Ions Name(s) Formula NH4+ Name(s) ammonium iodate IO3- acetate CH3COOC2H3O2- nitrate NO3- nitrite bromate BrO3- NO2- oxalate carbonate CO32- C2O42- perchlorate chlorate ClO3- ClO4- periodate chlorite ClO2- IO4- permanganate MnO4- peroxide O22- phosphate PO43- phosphite PO33- silicate SiO44- CrO42- chromate CN- cyanide Cr2O72- dichromate hydrogen carbonate bicarbonate HCO3- hydrogen sulfate bisulfate HSO4- sulfate Formula SO42- sulfite SO32- hydrogen phosphate biphosphate HPO42- thiocyanate SCN- hydroxide OH- thiosulfate S2O32- hypochlorite ClO- Other Ions copper (I) copper (II) iron (II) iron (III) lead (II) lead (IV) mercury (I) mercury (II) tin (II) tin (IV) cuprous cupric ferrous ferric plumbous plumbic mercurous mercuric stannous stannic Cu+ Cu2+ Fe2+ Fe3+ Pb2+ Pb4+ Hg22+ Hg2+ Sn2+ Sn4+