GeCn Coordination Polyhedra in the Crystal Structures

Abstract

A crystal-chemical analysis has been performed for germanium compounds whose structure includes GeCn coordination polyhedra using the intersecting sectors method and Voronoi–Dirichlet polyhedra. In the structures of organogermanium compounds, the germanium atoms have coordination numbers of 2–6 and 10 with respect to the carbon atoms. The influence of the coordination number and oxidation state of germanium atoms on the main characteristics of their Voronoi–Dirichlet polyhedra (VDP) was considered. The existence of a single linear dependence of the solid angles of VDP faces corresponding to valence and nonvalence Ge–C and Ge⋅⋅⋅C contacts on the corresponding internuclear distances was established. A stereo effect of the lone pair of electrons of Ge(II) atoms in the GeCn complexes (n = 2–6 or 10) found; it manifests itself as a displacement of the nuclei of Ge(II) atoms from the centers of gravity of their VDPs (0.15–0.58 Å) and as asymmetry of the coordination sphere. The deviation of the GeC3 complexes from planar geometry in the crystal structures was shown to be directly proportional to the displacement of the nuclei of Ge atoms from the centers of gravity of their VDP.