Stereochemistry of Bk, Cf, and Es in Oxygen-Containing Compounds

Abstract

Specific features of the coordination of the Bk, Cf, and Es atoms in the crystal structures of oxygencontaining compounds were considered using the Voronoi–Dirichlet polyhedra (VDPs). These actinides (An) form coordination polyhedra AnO_n (6 ≤ n ≤ 9) of five types. At a fixed An oxidation state, the An VDP volume is virtually independent of the coordination number n. Some parameters of the atomic VDPs in the An sublattices were characterized, and compounds in which binding An–An 5f interactions occur in the crystal structures were revealed. As demonstrated by the example of compounds containing coordination polyhedra AnO₉ (An = U–Cf) in the form of tricapped trigonal prisms, the VDP parameters can be used for evaluation of the actinide contraction of An(III) atoms in the crystal structures.