Structure and electron density of nickel potassium hydrogenbiscarbonate tetrahydrate

KNiH(CO3)2.4H2O, Mr=290.7, triclinic, Panti 1, a=5.3824 (2), b=6.6737 (2), c=6.9480 (2) A, α=115.881 (2), β=90.678 (2), γ=108.017 (2)deg, V=210.37 (1) A3, Z=1, Dx=2.31 Mg m-3, λ(Mo Kα)=0.71073 A, μ=2.859 mm-1, F(000)=148, T=298 K, R(F2)=0.0350 for 5228 unique reflections. Two carbonate groups are linked by a short hydrogen bond, with an O...O distance of 2.456 (2) A, forming a nearly planar centrosymmetric anion, [H(CO3)2]3-. The non-spherical distribution of the valence electrons was taken into account by deformation density refinements (Hirshfeld procedure). The deformation density maps are in good agreement with other experimental and theoretical studies. (orig.)