AnSen (An = Th, U, Np, Pu, Am, or Cm) Coordination Polyhedra in Crystal Structures

Abstract

Voronoi–Dirichlet (VD) polyhedra have been used to make a crystal-chemical analysis of compounds containing in their crystal structure coordination polyhedra AnSen (An = Th, U, Np, Pu, Am, or Cm). It was found that atoms An(II), An(III), An(IV), and An(V) occur in selenides. These atoms coordinate from 6 to 10 selenium atoms in the form of Se2– or Se–. It was shown that the VD polyhedra make it possible to determine the valence state of An atoms in structures of crystalline substances and reveal errors in the crystal-structural information. A dependence of the multiplicity of Se–Se bonds on their length in 0D, 1D, and 2D groups composed of only selenium atoms was determined.