Structures of mercury(II) halide adducts with transition-metal Lewis bases. Part I. Crystal structure of the dicarbonyl-π-cyclopentadienyl-cobalt complex with mercury(II) chloride
Crystals of (π-C5H5)(CO)2Cl,HgCl2 are monoclinic, P21/n, a= 7·85, b= 13·90, c= 9·38 Å, β= 91·1°, Z= 4. The structure was solved from photographic data by Patterson and Fourier methods and refined by block-diagonal least-squares analysis to a final R 0·093 for 1002 non-equivalent reflexions. The complex is a 1 : 1 Lewis acid-base adduct bonded through the metal atoms, the resulting Hg–Co bond length of 2·578 ± 0·004 Å is that expected for a covalent single bond. The idealised co-ordination about mercury is trigonal planar, but two long intermolecular Hg–Cl distances raise the effective co-ordination to trigonal bipyramidal.