Permanganate ion (MnO₄⁻)
- Charge
- −1
- Atoms
- Mn, O × 4
- Atoms in total
- 5
- Mass of the ion
- 118.934 g/mol
Permanganate is one manganese atom bonded to four oxygen atoms, with a 1− charge. Manganese is in its highest oxidation state, +7, and the four oxygens count −2 each, so the total is 7 − 8 = −1. Its solutions are deep purple, and potassium permanganate is used to treat drinking water and to run titrations in chemistry labs.
- Here per- marks a higher oxidation state rather than an extra oxygen: permanganate, MnO₄⁻, has manganese at +7, while manganate, MnO₄²⁻, has it at +6.
- When permanganate reacts in acid, its purple color fades as it turns into nearly colorless Mn²⁺, so it acts as its own indicator in titrations.
- Potassium permanganate, KMnO₄, is by far the most common permanganate salt.