Sodium manganate is the inorganic compound with the formulaNa<sub>2</sub>MnO<sub>4</sub>. This is a deep green solid is rarely encountered analogue of the related salt K<sub>2</sub>MnO<sub>4</sub>. Sodium manganate is rarely encountered because it cannot be readily prepared from by the oxidation of manganese dioxide and sodium hydroxide. Instead this oxidation stops at the level of Na<sub>3</sub>MnO<sub>4</sub>, and this Mn(V) salt is unstable in solution. Sodium manganate can be produced by reduction of sodium permanganate under basic conditions.