Vibrational spectra of R(PO3)(3) metaphosphates (R = Ga, In, Y, Sm, Gd, Dy)

A series of R(PO3)(3) (R = Ga, In, Y, Sm, Gd, Dy) metaphosphate crystals re presenting four different structural types were prepared and their vibratio nal spectra recorded. The distribution of internal and external chain modes was obtained taking into account the configuration (site symmetry) of the polyphosphate anions in the corresponding structures. The spectra presented reveal that the P-O- force constants are very sensitive to both the coordi nation of oxygen atoms and POP bond angles. The spectra of crystalline R(PO 3)(3) were compared with data for glassy metaphosphates. It was found that decreasing the size of R(III) cation leads to different structural effects in glasses and crystals of the same composition. Copyright (C) 2001 John Wi ley & Sons, Ltd.