| 摘要 |
A new low temperature layered manganese compound of the formula Ca2Mn3O8 has unexpectedly been synthesized in pure form. The unit cell dimensions of this new compound have been determined by X-ray diffraction and reveal that the compound is monoclinic with lattice parameters of a=11.02 A, b=5.85 A, c=4.94 A, alpha =90 DEG , beta =109.80 DEG , gamma =90 DEG . The structure consists of pseudohexagonal Mn4+sheets with similar oxygen sheets on either side, giving a distorted octahedral coordination to the Mn4+. Every fourth Mn4+is missing in these layers, so their composition is Mn3O8 with chains of coordination octahedra linked by common edges (rutile type arrangement). The Ca ions are situated between the Mn3O8 layers.
|
