Coordination polyhedra PdFn in crystals

The volume of the Voronoi-Dirichlet (VD) polyhedra of 35 types of palladium atoms with a fixed coordination number was found to regularly increase wit h a decrease in the oxidation number of the metal atom in the series (PdF6) -F-IV-(PdF6)-F-III-(PdF6)-F-II. At a fixed oxidation number of Pd, this vol ume increases with a decrease in the palladium coordination number in going from (PdF6)-F-II to (PdF4)-F-II. The increase in the VD polyhedron volume of Pd(II) atoms in going from the octahedral PdF64- complexes to the square -planar PdF42- complexes is rationalized by the appearance of the lone elec tron pair at the palladium atom. The volume of this pair is on average 6.1 Angstrom(3). The palladium coordination sphere is considered in terms of th e intersecting spheres method, which points to the occurrence of Pd-Q inter actions (Q is an alkali metal) in the structure of Q(3)PdF(5) and Q(2)PdF(4 ) fluorides.