Common Polyatomic Ions

NH₄⁺

ammonium

H₃O⁺

hydronium

CH₃COO⁻ or C₂H₃O₂⁻

acetate

CN⁻

cyanide

OH⁻

hydroxide

ClO⁻

hypochlorite

ClO₂⁻

chlorite

ClO₃⁻

chlorate

ClO₄⁻

perchlorate

NO₂^-

nitrite

NO₃^-

nitrate

MnO₄^-

permanganate

CO₃^2-

carbonate

HCO₃^-

hydrogen carbonate or bicarbonate

CrO₄^2-

chromate

Cr₂O₇^2-

dichromate

O₂^2-

peroxide

PO₄^3-

phosphate

HPO₄^2-

hydrogen phosphate

H₂PO₄^-

dihydrogen phosphate

SO₃^2-

sulfite

SO₄^2-

sulfate

HSO₄^-

hydrogen sulfate or bisulfate