Reference library

Polyatomic Ions

Useful polyatomic ion formulas and charges.

Common examples

NO₃⁻ nitrate; NO₂⁻ nitrite; SO₄²⁻ sulfate; SO₃²⁻ sulfite; CO₃²⁻ carbonate; HCO₃⁻ hydrogen carbonate; PO₄³⁻ phosphate; CH₃COO⁻ acetate; MnO₄⁻ permanganate.

Reading the charge

An ion’s net charge is written as a superscript. When creating a neutral ionic compound, balance total positive and negative charge rather than matching subscripts blindly.