Crystal structure of polymeric cadmium(II) malonate monohydrate

Abstract

Crystals of the title compound are trigonal (based on hexagonal axes), space group R, a=b= 17·216(9), c= 10·894(4)Å, α=β= 90, γ= 120°, Z= 18. The structure was determined from X-ray diffractometer data by Patterson and Fourier syntheses, and refined by full-matrix least-squares calculations to R 0·048 for 1071 observed reflections. Each malonate ligand chelates three symmetry-related cadmium atoms with two of the oxygen atoms also in bridging positions. The lattice formed is polymeric and further strengthened by hydrogen bonding via a co-ordinated water molecule. The cadium atom is seven-co-ordinate in nearly pentagonal bipyramidal geometry with Cd–O 2·272(7)–2·501(7)Å. The mode of chelation exhibited by the malonate ion has not previously been reported.