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That part of the field of single-crystal vibrational spectroscopy which is devoted to acquisition of well-proven assignments in terms of symmetry species is first placed within the wider context of solid state spectroscopy as a whole. Theoretical and practical factors which limit the size of crystal with which meaningful polarisation data can be obtained are then considered. Finally, brief summaries are given of selected areas of recent significant activity: chain and layer structures, silicates, and complexes with donor ligands.

A summary account is given of the phase transitions found at high pressure for several inorganic carbonyl and cyanide complexes: M(CO)6, (M = Cr, Mo, W); Re(CO)5Br; M2(CO)10, (M = Mn, Re) and MnRe(CO)10; Hg(CN)2; K2M(CN)4, (M = Zn, Cd, Hg); and K3Cu(CN)4. The structures of some of the phases have been deduced using group theoretical methods.

IR and Raman spectra of MCl2(meso-2,3-diaminobutane), (M = Pd, Pt), have been recorded down to liquid nitrogen temperature or lower. It is shown that correlation coupling occurs between closely spaced hydrogen-bonded pairs of molecules, which form a “super molecule,” but not between all eight molecules in the unit cell. The lattice mode region is also understood in outline on the basis of motions of the “super molecules” Methyl torsional modes appear to be near 140 cm−1.

Raman spectra of NaNO2 have been studied as a function of hydrostatic pressure to 40 kbar at 295 and 348 K. Slight changes in slope of mode frequency versus pressure plots support the view that a structural anomaly exists at 9 ± 1 kbar. The absence of qualitative changes in the Raman spectra allow the space group of NaNO2 IV to be specified as one of P1, P2, B2, Pm or Bm. The Raman spectrum of NaNO3 has been studied to 87 kbar. The changes observed are fully consistent with a second-order transition to a phase with symmetry C63v, as indicated by previous X-ray work, although the transition is sluggish.