Common Polyatomic ions Acetate CH3COO− or C2H3 Manganate MnO4− Amide NH2− Nitrate NO3− Ammonium NH4+ Nitrite NO2− Antimonate SbO43− Oxalate C2O42− Antimonite SbO33− Ozonide O3− Arsenate AsO43− Perbromate BrO4− Arsenite AsO33− Perchlorate ClO4− Azide N3− Permanganate MnO4− Benzoate C6H5COO− Peroxide O22− Bicarbonate HCO3− Peroxomonosulfate SO52− Borate BO33− Peroxodisulfate S2O82− Bromate BrO3− Pertechnetate TcO4− Bromite BrO2− Phosphate PO43− Carbide C22− Phosphite PO33− Carbonate CO32− Plumbate PbO32− Chlorate ClO3− Plumbite PbO22− Chlorite ClO2− Pyridinium C5H6N+ Chromate CrO42− Pyrophosphate P2O74− Chromite CrO2− Pyrylium C5H5O+ Chromyl CrO22+ Selenate SeO42− Citrate C6H5O73− Silicate SiO32− Cyanate OCN− Disilicate Si2O52− Cyanide CN− Orthosilicate SiO44− Dichromate Cr2O72− Periodate IO4− Disulfide S22− Pyrosilicate Si2O76− Ferrate FeO42− Stannate SnO32− Formate (formiate) HCO2− Stannite SnO22− Hydronium H3O+ Sulfate SO42− Hydroxide OH− Sulfite SO32− IO3− Tellurite TeO32− Thiosulfate S2O32− Iodate Iodite IO2−