Maximum filling principle and sublattices of actinide atoms in crystal structures

Abstract

The most important characteristics of the Voronoi-Dirichlet polyhedra (VDP) of A atoms (A is actinide) in chemically homogeneous sublattices in the crystal structures of 3479 inorganic, coordination, and organometallic compounds are determined. The effect of the actinide nature on the A-A interatomic distances in the crystal structures is considered. In the Th, U, Np, or Pu sublattices, VDP have most often 14 faces and the Fedorov cuboctahedron is the most abundant type of VDP, whereas in Ac, Pa, Am, Cm, Bk, or Cf sublattices, the VDP have mainly 12 faces and are shaped like rhomobododecahedra. In A sublattices that typically form VDP with 14 faces, the actinide atoms occupy, most often, sites with C 1 symmetry (47 to 59% of the sample size). In the case of actinides whose A sublattices tend to form VDP with 12 faces, the C 1 site symmetry is found either very rarely (Pa, Am, Cf) or not at all (Ac, Cm, Bk).