Raman spectroscopy of smithsonite

Raman spectroscopy at both 298 and 77 K has been used to study a series of selected natural smithsonites from different origins. An intense sharp band at 1092 cm(-1) is assigned to the CO32- symmetric stretching vibration. Impurities of hydrozincite are identified by a band around 1060 cm(-1). An additional band at 1088 cm(-1) which is observed in the 298 K spectra but not in the 77 K, spectra is attributed to a CO32- hot band. Raman spectra of smithsonite show a single band in the 1405-1409 cm(-1) range assigned to the v(3) (CO3)(2-) antisymmetric stretching mode. The observation of additional bands for the v(3)(g) modes for some smithsonites is significant in that it shows distortion of the ZnO6 octahedron. No v(2) bending modes are observed for smithsonite. A single band at 730 cm(-1) is assigned to the v(4) in phase bending mode. Multiple bands be attributed to the structural distortion are observed for the carbonate v(4) in phase bending modes in the Raman spectrum of hydrozincite with bands at 733, 707 and 636 cm(-1). An intense band at 304 cm(-1) is attributed to the ZnO symmetric stretching vibration. Copyright (c) 2007 John Wiley & Sons, Ltd.