Structure of calcium dizinc hexabromide hexahydrate Ca(H₂O)₆Zn₂Br₆

Abstract

Calcium dizinc bromide hexahydrate / Crystal structure, crystal chemistry / Complex ions / Crystal packingAbstract. [Ca(H 2 0) 6 ] [Zn 2 Br 6 ], M r = 758.36, monoclinic, C2/m, a = 13.276(6), b = 10.665(3), c = 13.785(7) Â, β = 113.30(3)°, V = 1792.2(12) Â\ Ζ = 4, D x = 2.81 Mg m" 3 , Motfoc radiation, λ = 0.71069 Â, μ =' 15.99 mm -1 , F(000) = 1400, room temperature, R = 0.055 (wR = 0.053) for 640 unique observed [/ > 3σ(7)] reflections. The structure consists of independent octahedral Ca(H 2 0)| + complexes «Ca-O) = 2.32 À) and dimeric tetrahedral Zn 2 Br|" complexes [<Zn -Br) = 2.48 (bridging) and 2.35 Â (terminal)] linked together by O -H...Br hydrogen bonds.The structure is related to those of MgZn 2 Br 6 · 6H 2 0 and ZnBr 2 · 2H 2 0 but the packing of the complex ions (and, hence, the hydrogen bonding) is different.