Inorganic Chemistry, Vol.36, No.11, 2248-2251, 1997
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 published 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 the positions of the water molecules. Instead of one type of H2O molecule being present as found in the original study, two sets of such molecules with four nonequivalent O ... Cl contacts were found. The presence, in the O-D stretching region of the spectra of samples with low deuterium content, of three bands with intensities close to 2:1:1 (rather 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.