DICESIUM TRANS-TETRAAQUADICHLOROCHROMIUM(III) CHLORIDE - REDETERMINATION OF THE CRYSTAL-STRUCTURE AND INFRARED STUDY OF THE WATER SPECTRUM

Infrared spectral studies of the solid led us to believe that the publ ished crystal structure of dicesium transtetraaquadichlorochromium(III ) chloride, trans-Cs-2[CrCl2(H2O)(4)]Cl-3 might be incorrect, Crystal data: Cs2CrCl5 . 4H(2)O, a = 17.484(9) Angstrom, b = 6.099(3) Angstrom , c = 6.928(3) Angstrom, beta = 106.06(5)degrees, monoclinic, C2/m, Z = 2 molecules per cell. The redetermination has revealed disorder in t he positions of the water molecules. Instead of one type of H2O molecu le being present as found in the original study, two sets of such mole cules with four nonequivalent O ... Cl contacts were found. The presen ce, in the O-D stretching region of the spectra of samples with low de uterium content, of three bands with intensities close to 2:1:1 (rathe r than the expected four) is believed to be a consequence of different degrees of nonlinearity of the two hydrogen bonds formed by the water molecules of one of the two existing types.