Common Polyatomic Ions

Cations and Anions

ammonium

ammonium

NH₄⁺

hydronium

H₃O⁺

acetate

CH₃COO^- or C₂H₃O₂^-

bromate

BrO₃^-

hypochlorite

ClO^-

chlorite

ClO₂^-

chlorate

ClO₃^-

perchlorate

ClO₄^-

cyanide

CN^-

dihydrogen phosphate

H₂PO₄^-

hydrogen carbonate (bicarbonate)

HCO₃^-

hydrogen sulfate (bisulfate)

HSO₄^-

hydroxide

OH^-

nitrite

NO₂^-

nitrate

NO₃^-

iodate

IO₃^-

periodate

IO₄^-

permanganate

MnO₄^-

carbonate

CO₃^-2

chromate

CrO₄^-2

dichromate

Cr₂O₇^-2

hydrogen phosphate

HPO₄^-2

oxalate

C₂O₄^-2

peroxide

O₂^-2

sulfite

SO₃^-2

sulfate

SO₄^-2

thiosulfate

S₂O₃^-2

phosphite

PO₃^-3

phosphate

PO₄^-3

arsenate

AsO₄^-3