Sodium manganate
Sodium manganate is the inorganic compound with the formula NaMnO. This deep green solid is a rarely encountered analogue of the related salt KMnO. Sodium manganate is rare because it cannot be readily prepared from the oxidation of manganese dioxide and sodium hydroxide. Instead this oxidation stops at the level of NaMnO, and this Mn(V) salt is unstable in solution. Sodium manganate can be produced by reduction of sodium permanganate under basic conditions: Because NaMnO is difficult to prepare, sodium permanganate is more expensive than potassium permanganate.