Crystal and molecular structure of cadmium diacetate dihydrate

Abstract

Crystals of the title compound are orthorhombic, a= 8·690(2), b= 11·920(2), c= 8·100(2)Å, Z= 4, space-group P2₁2₁2₁. The structure was determined from diffractometer data by Patterson and Fourier syntheses, and refined by full-matrix least-squares calculations to R 0·028 for 1292 observed reflexions. The cadmium is co-ordinated to seven oxygen atoms; the co-ordination is best described by a distorted square base-trigonal cap geometry. Both acetate groups are bidentate, although the oxygen atom, O(1), of one of them, is also in a bridging position forming a continuous cadmium–oxygen spiral around the two-fold screw axis parallel to c. There are two distinct Cd–O distances, involving both acetate groups : Cd–O(2) 2·294(4), Cd–O(1) 2·597(4), Cd–O(3) 2·304(4), and Cd–O(4) 2·546(4)Å. This may be expected for the acetate group containing the bridging oxygen, O(1), but it is somewhat surprising to find long and short Cd–O bonds in the acetate not having a bridging oxygen. There is an extensive hydrogen-bonding network which reinforces the Cd–O spiral and also links spirals.