The composition corresponded to that of potassium manganate. Manganate(V) is a tetrahedral oxyanion structurally similar to sulfate, manganate, and permanganate. Lanthanum strontium manganate (LSM) is the most common oxygen electrode material. One example is the reaction of oxalic acid with acidified potassium permanganate (or manganate (VII)). It is sometimes considered to be a hydrous manganese manganate, but of doubtful composition. Potassium manganate is the inorganic compound with the formula KMnO. Sodium manganate is the inorganic compound with the formula NaMnO. Barium manganate has also been used to oxidize hydrazones to diazo compounds. Barium manganate can appear as a dark blue or green to black crystals. Barium manganate is indefinitely stable, active and can be stored for months in dry conditions. Manganate should not to be confused with permanganate in which contains manganese(VII).