Manganese Stereochemistry in the Structures of Oxygen-Containing Compounds

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 MnOn 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 Å), 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 manganites with giant magnetoresistance.