SYNTHESIS AND MOLECULAR-STRUCTURE OF NI5SB3O2(OET)15(HOET)4

A new Ni-Sb alkoxide of the formula Ni5Sb3O2(OEt)15(HOEt)4 has been prepared by reacting anhydrous NiCl2 with NaSb(OEt)4 and NaOEt in a toluene/ethanol solution in dry, oxygen-free atmosphere. Ni5Sb3O2(OEt)15(HOEt)4 crystallizes in the noncentrosymmetric space group Pca2(1), with a = 17.909 (2) angstrom, b = 20.608 (3) angstrom, c = 17.221 (2) angstrom, V = 6356 (1) angstrom 3, Z = 4, D(x) = 1.621 (4) g/cm3, and fw = 1550.89. The crystal structure was refined to R = 0.041 (R(w) = 0.050) for the 3049 most significant single-crystal X-ray diffraction intensities collected with Mo K-alpha radiation (lambda(Mo K-alpha) = 0.7107 angstrom, mu-(Mo K-alpha) = 27.8 cm-1) at room temperature (T = 293 (1) K). The packing of the wedge-shaped molecules can be considered as body-centered cubic. One of the Sb atoms is four-coordinated by the oxygen atoms, while the other two are five-coordinated. The Sb atoms are all trivalent, and the stereoactive lone pairs complete the coordinations. Thus, the coordinations around the Sb atoms become distorted trigonal-bipyramidal and octahedral, respectively. Three of the five Ni atoms are approximately octahedrally coordinated by oxygen atoms, and the remaining two Ni atoms five-coordinated in the shape of a distorted square pyramid.