Sodium permanganate

Preparation and properties

Sodium permanganate cannot be prepared analogously to the route to KMnO₄ because the required intermediate manganate salt, Na₂MnO₄, does not form. Thus less direct routes are used including conversion from KMnO₄.

Sodium permanganate behaves similarly to potassium permanganate. It dissolves readily in water to give deep purple solutions, evaporation of which gives prismatic purple-black glistening crystals of the monohydrate NaMnO₄·H₂O. The potassium salt does not form a hydrate. Because of its hygroscopic nature, it is less useful in analytical chemistry than its potassium counterpart.

It can be prepared by the reaction of manganese dioxide with sodium hypochlorite:

2 MnO₂ + 3 NaClO + 2 NaOH → 2 NaMnO₄ + 3 NaCl + H₂O