Raman and infrared study of phyllosilicates containing heavy metals (Sb, Bi): Bismutoferrite and chapmanite

Abstract

The kaolinite-like phyllosilicate minerals bismutoferrite BiFe3+2Si2O8(OH) and chapmanite SbFe3+2Si2O8(OH) have been studied by Raman spectroscopy and complemented with infrared spectra. Tentatively interpreted spectra were related to their molecular structure. The antisymmetric and symmetric stretching vibrations of the Si-O-Si bridges, δ SiOSi and δ OSiO bending vibrations, ν (Si-Oterminal)- stretching vibrations, ν OH stretching vibrations of hydroxyl ions, and δ OH bending vibrations were attributed to the observed bands. Infrared bands in the range 3289-3470 cm-1 and Raman bands in the range 1590-1667 cm-1 were assigned to adsorbed water. O-H···O hydrogen-bond lengths were calculated from the Raman and infrared spectra. © 2009 John Wiley & Sons, Ltd.