Crystal structure of CaZn2(OH)(6)center dot 2 H2O

The electrochemical oxidation of zinc in a zinc/ iron-pair leads in an aqueous NH3 solution of calciumhydroxide at room temperature to colourless crystals of CaZn2(OH)(6) . 2 H2O. The X-ray structure determination was now successful including all hydrogen positions. P2(1)/c, Z = 2, a = 6.372(1) Angstrom, b = 10.940(2) Angstrom, c = 5.749(2) Angstrom, beta = 101.94(2)degrees. N(F-o(2) greater than or equal to 3 sigma F-o(2)) = 809, N(Var.) = 69, R/R-w = 0.011/0.012 The compound CaZn2(OH)(6) . 2 H2O contains Zn2+ in tetrahedral coordination by OH- and Ca2+ in octahedral coordination by four OH- and two H2O. The tetrahedra around Zn2+ form corner sharing chains, three-dimensionally linked by isolated polyhedra around Ca2+. Weak hydrogen bridge bonds result between H2O as donor and OH-.