Stereochemistry of Plutonium in Oxygen-Containing Compounds

The coordination of 122 crystallographically nonequivalent Pu(III, IV, V, VI, VII) atoms in the crystal structures of all the oxygen-containing compounds characterized with the R-factor lower than 0.1 was analyzed with the aid of Voronoi–Dirichlet polyhedra (VDPs). The Pu atoms form PuO _n coordination polyhedra (6 ≤ n ≤ 12) of 14 types. At a fixed oxidation state of the Pu atoms, the plutonium VDP volume in PuO _n complexes is virtually independent of the coordination number n. The rule of 14 neighbors is fulfilled in sublattices consisting of Pu atoms (Pu sublattices). Analysis of the PVD characteristics in Pu sublattices revealed compounds in which the occurrence of bonding Pu–Pu 5f interactions can be assumed. As demonstrated by the example of Pu(III), the VDP parameters can be successfully used for finding the most adequate 4f surrogates for highly radioactive transuranium elements.