Abstract: | Crystal Structure of CaZn2(OH)6 · 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. P21/c, Z = 2, a = 6.372(1) Å, b = 10.940(2) Å, c = 5.749(2) Å, β = 101.94(2)° N(F ≥ 3σF ) = 809, N(Var.) = 69, R/RW = 0.011/0.012 The compound CaZn2(OH)6 · 2H2O 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?. |