Sodium manganate

Sodium manganate is the inorganic compound with the formula Na₂MnO₄. This deep green solid is a rarely encountered analogue of the related salt K₂MnO₄. Sodium manganate is rarely encountered because it cannot be readily prepared from the oxidation of manganese dioxide and sodium hydroxide. Instead this oxidation stops at the level of Na₃MnO₄, and this Mn(V) salt is unstable in solution. Sodium manganate can be produced by reduction of sodium permanganate under basic conditions:

Because NaMnO₄ is difficult to prepare, sodium permanganate is more expensive than potassium permanganate.