Vibrational spectroscopy of some inorganic single crystals.

A brief introduction is given to the vibrational spectra of crystals, and to other relevant topics such as their symmetry and optical properties. Some practical aspects of the study of crystals by infra-red and Raman spectroscopy are described. The single-crystal vibrational spectra of [Ni (H20)6] [SnC16] are reported, and a complete assignment is offered for the low-frequency region. The complete Raman spectra of SrC12.6H20 and two related crystals are reported. A complete assignment is offered for the low-frequency region, and some assignments are proposed for the other regions. Splitting of longitudinal and transverse optic modes is observed. Certain aspects of the spectra are interpreted in terms of disorder associated with hydrogen atoms. Vibrational spectra of single crystals of Cu (dmso)2C12 are reported. The coupling of vibrations in the unit cell is discussed, and an assignment is proposed. This is discussed in relation to the spectra of other (dmso) complexes. Input data for a normal coordinate analysis of this compound are listed. Vibrational spectra of single crystals of [Co (imidazole)6 (N03)2 are reported, and a complete assignment offered for the low-frequency region. Polarised-i.r. spectra of two triclinic crystals are reported and interpreted in terms of molecular symmetry. In the case of Rh(C0)2(acac) the results enable distinction between in-plane and out-of-plane vibrations. A partial assignment is offered for V0(acac)2.