A vibrational spectroscopic study of some inorganic single crystals.

A brief introduction to certain practical and theoretical aspects of the study of the vibrational spectra of crystals is given. The major part of the work presented concerns the assignment of the vibrational modes of some metal carbonyl compounds, detailed below. Single crystal infrared reflectance experiments (and transmission experiments for the 20 to 200 cm-1 region) have been obtained for the hexacarbonyls of chromium, molybdenum and tungsten at 100 K. These have been combined with low temperature single crystal Raman data in order to provide a more complete assignment of the spectra of these species. A study of the vibrational spectra of the decacarbonyls and bromopenta-carbonyls of manganese and rhenium has enabled a more detailed and internally consistent assignment to be proposed for their spectra. Infrared data at c. 100 K have been collected for Fe2 (CO)9 in the 20 to 250 cm-1 region using polycrystalline samples, and these are supplemented by infrared reflectance data for the 200 to 2500 cm-1 region. Combining this work with existing Raman data this led to an assignment which reveals substantial coupling between the two sets of terminal carbonyl groups. An assignment for the v(CO) region for the dodecacarbonyls of ruthenium and osmium is offered on the basis of a single crystal infrared reflectance study, in combination with existing Raman data. Low temperature infrared data for Ir4 (CO)12 have been obtained from 20 to 2500 cm-1, and these are supplemented by new ambient temperature Raman data. The construction of the spectrum is accounted for on the basis of a coupling scheme. The final chapter is concerned with the identification of the libration- al modes of water; after an introduction to the topic, which highlights some of the difficulties in assigning these modes, the librational modes of water in CsMnCl3.2H2O are assigned.