Raman scattering in BIMEVOX (ME = Mg, Ni, Cu, Zn) single crystals

The Raman spectra of BIMEVOX (ME = Mg, Ni, Cu, Zn) single crystals are reported. The main features of the spectra observed in the 600 to 900 cm(-1) frequency range are assigned to the stretching vibrations of the V-O bonds. Interpretation of the Raman spectra is based on the diatomic approximation and the correlation between the frequencies of stretching vibrations of vanadium-oxygen bonds and bond lengths. V-O bond orders are determined from an empirical relation between these frequencies and bond orders. The results point to predominantly tetrahedral coordination of vanadium in the studied BIMEVOX systems. (C) 2000 Elsevier Science B.V. All rights reserved.