Polyatomic Ions

Hypobromite BrO⁻ / Bromate BrO₃⁻ / Perbromate BrO₄⁻ Arsenate AsO₄⁻³ Posphite PO₃⁻³ Phosphate PO₄⁻³ Peroxide O₂⁻² Oxalate C₂O₄⁻² Dichromate Cr₂O₇⁻² Chromate CrO₄⁻² Sulfite SO₃⁻² Sulfate SO₄⁻² Carbonate CO₃⁻² Bicarbonate HCO₃⁻ Permanganate MnO₄⁻ Acetate C₂H₃O₂⁻ Thiocyanate SCN⁻ Cyanide CN⁻ Hydroxide OH⁻ Nitrite NO₂⁻ Nitrate NO₃⁻ Hypoiodite IO⁻ Iodite IO₂⁻ Iodate IO₃⁻ Periodate IO₄⁻ Hypochlorite ClO⁻ Chlorite ClO₂⁻ Chlorate ClO₃⁻ Perchlorate ClO₄⁻ Ammonium NH₄⁺ Mercury (mercurous) Hg₂²⁺