DIFFERENCE THERMOANALYSIS OF THE FORMATION AND X-RAY STRUCTURAL-ANALYSIS OF PENTASTRONTIUM CHLORIDE PHOSPHATE

Polycrystalline materials of pentastrontium chloride phosphate were prepared by solid state reaction. The reaction mechanisms were studied by differential thermal analysis of the single starting materials and their mixture at temperatures ranging from 25 to 1200 degrees C. The loss in weight determined experimentally is in the range of the calculated values. It could be shown by X-ray diffraction analysis of the samples that the use of boric acid at the preparation does not result in the formation of pentastrontium chlorideboratephosphate as described by Nakamoto et al. but in the formation of Sr-5(PO4)(3)Cl and Sr2B5O9Cl. Pentastrontium chloridephosphate crystallizes in the hexagonal system with space group P6(3)/m. Samples prepared without or with boric acid show the same lattice parameters and only small differences in the atomic coordinates. Pentastrontium chloridephosphate is the starting point for alkaline earth halidephosphates activated by divalent europium, which are used as a blue component in three band fluorescent lamps.