Polyatomic Ions: Names and Formulas (AP)

Hydroxide ion

Hydroxide ion

OH⁻

Nitrite ion

NO₂⁻

Nitrate ion

NO₃⁻

Bicarbonate (hydrogen carbonate) ion

HCO₃⁻

Carbonate ion

CO₃²⁻

Acetate ion

CH₃COO⁻ or C₂H₃O₂⁻

Sulfite ion

SO₃²⁻

Sulfate ion

SO₄²⁻

Phosphate ion

PO₄³⁻

Ammonium ion

NH₄⁺

Hypochlorite ion

ClO⁻

Chlorite ion

ClO₂⁻

Chlorate ion

ClO₃⁻

Perchlorate ion

ClO₄⁻

Hydrogen sulfate ion

HSO₄⁻

Cyanide ion

CN⁻

Permanganate ion

MnO₄⁻

Thiocyanate ion

SCN⁻

Phosphite ion

PO₃⁻

Oxalate ion

C₂O₄²⁻

Chromate ion

CrO₄²⁻

Dichromate ion

Cr₂O₇²⁻

Peroxide ion

O₂²⁻