PREPARATION OF MONODISPERSED MANGANESE (IV) OXIDE PARTICLES FROM MANGANESE (II) CARBONATE

Spherical and monoclinic-like manganese (IV) oxide particles of moderately narrow size distribution were prepared by conversion of carbonates obtained by simple mixing and aging procedures. The conversion of manganese (II) carbonates gave gamma -manganese (IV) oxide particles having the composition MnO//1//. //8//0// minus //1//. //9//0 and retaining the morphology of the mother crystals under air (300-400 degree C) and oxygen (400 degree C) atmospheres. The isoelectric point and point of zero charge of the oxides thus obtained were determined as pH 3. 5 and 4. 0, respectively.