Crystal structure and thermal decomposition studies of barium borophosphate, BaBPO5

The crystal structure and thermal decomposition process of barium borophosphate BaBPO5 have been studied by a combination of X-ray powder diffraction (XRD) and vibration spectroscopic techniques, The structure of BaBPO5 is refined by Rietveld technique, which indicates that the structure units of this compound are PO4 and BO4 tetrahedra as well as irregular rare earth polyhedra, The thermal decomposition process of BaBPO5 have been observed by the XRD patterns of decomposition samples under a series of heat treatments, The Raman and infrared spectra of the initial compound BaBPO5 and its decomposed products Ba3BP3O12 and Ba2P2O7 showed the variations of the anion groups of boron and phosphorus, Assignments have been deduced from the systematic investigation of natural compounds and isotopic species with the help of isotopic shift data of B-10-B-11. (C) 1998 Academic Press.