common polyatomic ions (copy reverse)

Mercury(I)

Hg2 +2

Ammonium

NH4 +1

Nitrite

NO2 -1

Nitrate

NO3 -1

Sulfite

SO3 2-

Sulfate

SO4 2-

Hydrogen Sulfate

HSO4 1-

Hydroxide

OH -1

Cyanide

CN -1

Phosphate

PO4 -3

Hydrogen phosphate

HPO4 2-

Dihydrogen Phosphate

H2PO4 -1

Thiocyanate

NCS -1

Carbonate

CO3 -2

hydrogen carbonate

HCO3 -1

Hypochlorite

CIO -1

chlorite

CIO2 -1

Chlorate

CIO3 -1

Perchlorate

CIO4 -1

Acetate

C2H3O2 -1

permanganate

MnO4 -1

Dichromate

Cr2O7 -2

Chromate

CrO4 -2

Peroxide

O2 -2

Oxalate

C2O4 -2

Thiosulfate

S2O3 -2