The crystal structure of Thorium(IV)tetrakis(trifluoroacetylacetonate)

The crystal structure of the compound thorium(IV)tetrakis(trifluoro-acetylacetonate) was determined by means of a threedimensional X-ray analysis. The space group is C2/c and the cell dimensions are a = 25,05 Å, b = 6.43 Å, c = 21.3 Å, β = 125.4°, with Z = 4. The thorium atom is coordinated by 8 oxygen atoms in the form of an 1111 (D₄–422) antiprism. The mean of the Th–O distances is 2.39 Å with a standard deviation ± 0.04 Å. The trifluoroacetylacetonate rings are approximately planar, except for the CH₃ and CF₃ groups which show significant deviations. The Th–O bonds form angles of approximately 72° and 50° with the theoretical 8 -axis of the antiprism. The structure is stabilized by VAN DER WAALS contacts between neighbouring molecules. The refinement of the atomic positions, the anisotropic temperature parameter of thorium and isotropic temperature parameters of all the other atoms by the least squares method, has given a reliability index of 0.148.