Manganese Stereochemistry in the Structures of Oxygen-Containing Compounds

摘要

The Voronoi-Dirichlet polyhedra(VDP)and the method of intersecting spheres were used to carry out crystal chemical analysis of coordination of 1304 sorts of Mn atoms in the structure of 859 oxygen-containing compounds.The manganese atoms whose oxidation number varies from 2 to 7 were found to bind 4 to 8 oxygen atoms giving rise to the MnO_n coordination tetrahedra(n = 4),square pyramids(n = 5),octahedra or trigonal prisms(n = 6),pentagonal bipyramids or one-cap trigonal prisms(n = 7),trigonal dodecahedra,cubes,square antiprisms,or hexagonal bipyramids(n = 8).The effect of the valence state and the coordination number of manganese atoms on the parameters of their VDP was studied.The existence of a general linear correlation between the solid angles of the VDP faces corresponding to Mn-O bonds and the corresponding interatomic distances,which vary over a broad range(1.55-3.12 A),was established.The VDP characteristics can be used to determine the valence state of Mn atoms in the crystal structures and in the crystal chemical analysis of man-ganites with giant magnetoresistance.