Polyatomic Ion Groups

Nitrate

NO₃^-1

Carbonate

CO₃^-2

Sulfate

SO₄^-2

Phosphate

PO₄^3-

Chlorate

ClO₃^-1

Acetate

C₂H₃O₂^-1

Chromate

CrO₄^-2

Nitrite

NO₂^-1

Sulfite

SO₃^-2

Chlorite

ClO₂^-1

Phosphite

PO₃^3-

Hydrogen Carbonate

HCO₃^-1

Hydrogen Sulfate

HSO₄^-1

Ammonium

NH₄⁺¹

Permanganate

MnO₄^-1

Cyanide

CN^-1

Hydroxide

OH^-1

Hypochlorite 

ClO^-1

Perchlorate

ClO₄^-1

Oxalate

C₂O₄^-2

Dichromate

Cr₂O₇^-2

Silicate

SiO₃^-2

Hydrogen Sulfite

HSO₃^-1