Common Polyatomics

Ammonium ion

NH₄⁺

Hydronium ion

H₃O⁺

Acetate ion

C₂H₃O₂^-

Arsenate ion

AsO₄^3-

Carbonate ion

CO₃^2-

Hypochlorite ion

ClO^-

Chlorite ion

ClO₂^-

Chlorate ion

ClO₃^-

Perchlorate ion

ClO₄^-

Chromate ion

CrO₄^2-

Dichromate ion

Cr₂O₇^2-

Cyanide ion

CN^-

Hydroxide ion

OH^-

Nitrite ion

NO₂^-

Nitrate ion

NO₃^-

Oxalate ion

C₂O₄^2-

Permanganate ion

MnO₄^-

Phosphate ion

PO₄^3-

Sulfite ion

SO₃^2-

Sulfate ion

SO₄^2-

Thiocyanate ion

SCN^-

Thiosulfate ion

S₂O₃^2-