Polyatomic anions and cations

hydroxide ion

OH-

perchlorate ion

ClO4 -

hypochlorite ion

OCl-

nitrate ion

NO3 -

nitrite ion

NO2 -

carbonate ion

CO3 2-

bicarbonate ion

HCO3 -

phosphate ion

PO4 3-

phosphite ion

PO3 3-

sulfate ion

SO4 2-

sulfite ion

SO3 2-

acetate ion

CH3CO2 - or C2H3O2 -

cyanide ion

CN-

oxalate ion

C2O4 2-

ammonium ion

NH4 +

hydronium ion

H3O+