Journal of Crystal Growth, Vol.434, 30-35, 2016
Nitrate (chloride) melts as media for crystal growth of complex phosphates of alkali and trivalent metals
The interaction in the molten systems (MPO3)-P-I-(MY2O3)-O-III-(MNO3)-N-I ((MCI)-C-I) (M-I - Na, K; M-III - Al, Fe, Y, Bi) was investigated at molar ratios P/M-III = 1 or 3 at the temperatures 400 degrees C (for (MNO3)-N-I) or 810 degrees C (for MICI). Formation conditions of complex phosphates M-3(I)/M-2(III)/(PO4)(3) and (M3M2III)-M-I(PO4)(2) (M-I - Na, K; M-III - Al, Fe, Bi) were established. It was shown that the crystal size of obtained phosphates can be controlled by using different salt melts. The synthesized compounds were characterized using powder X-ray diffraction, Fourier transform infrared spectroscopy, Optical microscopy and Scanning electron microscopy with Energy-dispersive X-ray spectroscopy. Differential thermal data for Na3Bi(PO4)(2) and Na3Fe(PO4)(2) showed congruent and incongruent melting, respectively. (C) 2015 Elsevier B.V. All rights reserved.