Experimental and theoretical deformation electron density for vanadyl sulfate hexahydrate

Pentaaquaoxovanadium(IV) sulfate monohydrate, [VO(H2O)5]2+[SO4]2-, H2O, Mr = 271.09, triclinic, Panti 1, a = 6.190(1), b = 7.471(1), c = 10.100(1) A, α = 92.28(1), β = 101.96(1), γ 95.35(1)deg, V = 454.1(1) A3, Z=2, Dx=1.983(1) g cm-3, λ(Mo Kα) = 0.71073 A, μ = 13.2 cm-1, F(000) = 258, T = 120(1) K. Single-crystal X-ray data with aspherical multipole expansion of the electron density gave R(F2) = 0.0177 for 3367 observed unique reflections with sinθ/λ < 0.79 A-1. Experimental deformation densities were calculated using thermal parameters from high-angle X-ray refinement (0.79 < sinθ/λ < 1.20 A-1). The densities have been compared with corresponding theoretical results obtained from ab initio calculations of multi-configurational self-consistent-field type, using an extended Gaussian basis set. Densities for the V-O bond, the oxygen lone pairs and the non-bonding d electron compare favorably on the qualitative level. There are quantitative differences, some of which may be explained by thermal smearing. (orig.)