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Solid solutions KTi1-XHfXOPO4 (х = 0.008 - 0.107) possessing the KTiOPO4 structure, have been synthesized in molten system K2O-P2O5-TiO2-HfF4. The crystal growth experiment of Hf-doped KTP crystal has been reported. The X-ray powder diffraction data and chemical analysis are also presented. It has been shown that KTiOPO4 crystal structure slightly changes when Hf incorporates into the framework. Transmission/absorption spectra of KTi0.974Hf0.026OPO4 crystals have been recorded. The incorporation of Hf ions shifts the optical absorption edge in the UV-visible spectrum towards the long-wavelength region with absorption near 387 nm. [ABSTRACT FROM AUTHOR]

Abstract: The crystallization of complex phosphates from the melts of Cs2O–P2O5–CaO–M III 2O3 (M III—Al, Fe, Cr) systems have been investigated at fixed value Cs/P molar ratios equal to 0.7, 1.0 and 1.3 and Са/Р=0.2 and Ca/М III=1. The fields of crystallization of CsCaP3O9, β-Ca2P2O7, Cs2CaP2O7, Cs3CaFe(P2O7)2, Ca9 M III(PO4)7 (M III—Fe, Cr), Cs0.63Ca9.63Fe0.37(PO4)7 and CsCa10(PO4)7 were determined. Obtained phosphates were investigated using powder X-ray diffraction and FTIR spectroscopy. Novel whitlockite-related phases CsCa10(PO4)7 and Cs0.63Ca9.63Fe0.37(PO4)7 have been characterized by single crystal X-ray diffraction: space group R3c, a=10.5536(5) and 10.5221(4)Å, с=37.2283(19) and 37.2405(17)Å, respectively. [Copyright &y& Elsevier]