Crystal Structure and Thermal Decomposition Studies of Barium Borophosphate, BaBPO5

The crystal structure and thermal decomposition process of barium borophosphate BaBPO5have been studied by a combination of X-ray powder diffraction (XRD) and vibration spectroscopic techniques. The structure of BaBPO5is refined by Rietveld technique, which indicates that the structure units of this compound are PO4and BO4tetrahedra as well as irregular rare earth polyhedra. The thermal decomposition process of BaBPO5have been observed by the XRD patterns of decomposition samples under a series of heat treatments. The Raman and infrared spectra of the initial compound BaBPO5and its decomposed products Ba3BP3O12and Ba2P2O7showed 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 of10B–11B.