Über Oxidhydroxide des vierwertigen Mangans mit Schichtengitter. 1. Mitteilung. Natriummangan (II, III)manganat(IV)

The preparation of Na 4 Mn 14 O 27 , 9H 2 O (hitherto named manganomanganite or δ‐MnO 2 ) by oxidation of a fresh Mn(OH) 2 suspension in aqueous NaOH by molecular oxygen, and its probable structure are described. It is a double layer manganate (IV) structure resembling other manganates such as chalcophanite. Orthorhombic unit cell parameters are, a 0 = 8,54, b 0 = 15,39, c 0 = 14,26 Å. In diluted nitric acid topotactical transition to manganese (III) manganate (IV), Mn 7 O 13 .5H 2 O (unit cell: a 0 = 2,84, c 0 = 7,27 Å; primitively hexagonal), and by prolonged digestion to nsutite, γ‐MnO 2 , occurs.