polyatomic ions

NH4

ammonium

OH

hydroxide

NO3

nitrate

NO2

nitrite

N3

azide

C2H3O2

acetate

ClO4

perchlorate

ClO3

chlorate

ClO2

hypochlorite

MnO4

permanganate

HCO3

bicarbonate (hydrogen carbonate)

CN

cyanide

HSO4

bisulfate (hydrogen sulfate)

HSO3

bisulfite (hydrogen sulfite)

H2PO4

dihydrogen phosphate

SO4

sulfate

SO3

sulfite

S2O3

thiosulfite

CO3

carbonate

CrO4

chromate

Cr2O7

dichromate

HPO4

hydrogen phosphate

C2O4

oxalate

PO4

phosphate

PO3

phosphite