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Examples of a class of glassy biomaterials with chemical composition similar to that of bone have been prepared by heating mixtures of calcium metaphosphate and hydroxylapatite. The Raman and infrared spectra of these materials are reported and discussed in relation to glass structure, which is of the linear polymeric type with chain length depending on the molar ratio R=[CaO]/[P2O5]. The products of the thermal decomposition of hydroxylapatite have also been characterized spectroscopically.

The Raman spectra of the cyclohexyl halide-thiourea clathrates have been investigated. It is found that whereas cyclohexyl chloride and bromide exist only in the axial conformation in the clathrate, cyclohexyl iodide exists in both the axial and equatorial conformations in the clathrate.

Urea/n-paraffin clathrates enable Raman spectroscopic studies of oriented single n-paraffin molecules in the extended planar zig-zag configuration to be made. Raman spectra in the region 0–3500 cm−1 are reported for various orientations of single crystals of the following urea and urea-d4/n-paraffin clathrates: urea/n-tetradecane, urea/n-hexadecane and urea/n-undecane. Assignments have been made for the vibration of the urea host lattice and the guest n-paraffin molecules in the extended planar zig-zag configuration, utilising the orientation measurements.

The Raman spectra in the lattice region (0–400 cm−1) of single crystals of NaNH4SO4·2H2O in various orientations are reported for the temperature range 293–87 K. NaNH4SO4·2H2O undergoes a transition at 101 K from a paraelectric phase to a ferroelectric phase. The changes in the Raman spectra as the crystal is cooled support the evidence from magnetic resonance studies that a large lattice distortion occurs at the transition temperature.

The Raman spectra of single crystals of NaNH4SeO4·2H2O in various orientations are reported for the temperature range 293–89 K. NaNH4SeO4·2H2O undergoes a transition at 180 K from a paraelectric phase to a ferroelectric phase. The changes in the Raman spectra as the crystal is cooled support the evidence from magnetic resonance studies that the transition is of a displacive type with an associated overdamped soft mode. Ordering of the NH ions but not of the complete crystal occurs at the transition temperature.

Experimental studies of the variation of intensity with excitation wavenumber of various vibrational bands in the Stokes Raman spectra of the following molecules are reported: naphthalene, pyrazine, phenazine, cinnoline and quinazoline. The results are discussed in terms of the Albrecht–Hutley theory of pre-resonance Raman intensities and the electronic states involved in the pre-resonance enhancement identified.

The Raman spectra in the region 250–1000 cm−1 are reported for six orientations of a single crystal of K2SeO4 over the temperature range 293–87 K. In the spectra of the paraelectric phase at 293 K, splitting of the internal vibrations of the SeO ion is in accord with the predictions of group theory. No significant differences are found in this internal frequency region in the ferroelectric phase at 87K. It is concluded that only minor lattice distortions are occurring at the ferroelectric phase transition which may be associated with a soft mode in the 22 cm−1 region.

Experimental studies of the variation of intensity with excitation wavenumber of some a1 vibrational bands in the Stokes Raman spectra of the following molecules are reported: quinoxaline (1,4-diazanaphthalene), phthalazine (2,3-diazanaphthalene) and pyridazine (1,2-diazabenzene). The results are discussed in terms of the Albrecht–Hutley theory of pre-resonance Raman intensities and the electronic states involved in the pre-resonance enhancement identified.

The Raman spectra in the region 400–4000 cm−1 of single crystals of NaNH4SO4·2H2O in various orientations are reported for the temperature range 293–87K. NaNH4SO4·2H2O undergoes a transition at 101 K from a paraelectric phase to a ferroelectric phase. The changes in the Raman spectra of the constituent species, NH, SO and H2O as the temperature is lowered indicate that below the phase transition there are non-equivalent ions in the unit cell. The abruptness of the spectral changes at 101 K suggests a large lattice distortion in accord with the predictions of magnetic resonance studies.

The [I2CN]− ion, previously only known in aqueous solution, has been isolated as its caesium salt; and the previously unknown [BrICN]− ions [ClICN]− have been isolated as their caesium salts. The Raman and IR vibrational spectra of these three caesium salts have been investigated in detail and indicate that the halide ions coordinate to the I atom of ICN to form linear (C∞ν) [X—I—CN]− ions (X=I, Br or Cl), contained in a centrosymmetric unit cell. This C∞ν structure is supported by a normal coordinate analysis for the [IICN]− ion.

Resonance Raman spectra (RRS) of azobenzene, 4-aminoazobenzene, 4-methylaminobenzene and 4-dimethylaminoazobenzene in the solid state and in a range of solvents have been recorded. The RRS of the 4-aminoazobenzenes are much more solvent dependent than those of azobenzene. Their electronic absorption spectra suggest that their azo-nitrogens are strongly hydrogen bonded in aqueous media. The RRS were interpreted in terms of intra- and inter-molecular interactions. These molecules probably have a near-planar geometry in both the solid state and in aqueous media owing to intermolecular interactions. The intramolecular interactions of the nNN orbitals with the π MOs tend to cause ring twisting about the axis of the NN bond. The RRS of the aminoazobenzenes in non-polar solvents show differences from that of the powder, and these could only be attributed to the formation of non-planar structures.

Improved room temperature Raman spectra obtained from oriented single crystals of K2SeO4 of high quality are reported and discussed. The new results show that some of the earlier spectra contained spurious bands and that some genuine bands were incorrectly assigned.

Crystals of semicarbazide hydrochloride, NH2CONHNH+3Cl– are paraelectric above 294 K and ferroelectric below. The Raman spectra in the region 0–1800 cm–1 of oriented single crystals of semicarbazide hydrochloride and its perdeutero analogue have been recorded over the temperature range 298–87 K. In addition the infrared spectrum of semicarbazide hydrochloride in a KBr disc at 298 K has been recorded in the range 250–1700 cm–1. The Raman spectra have been analysed in relation to the structural changes occurring with the change of phase. The spectroscopic results support the X-ray evidence that the transition to the ferroelectric phase is second order and involves no major structural change. Comparison of the infrared and Raman spectra suggest that LO–TO splitting is unimportant.