Phase formation of complex phosphate K4Ti3Ni(PO)(4) in K2O-P2O5-TiO2-NiO melt solutions

The principles of complex phosphate crystallization in K2O-P2O5-TiO2-NiO solution melts are studied for the ratios K/P = 0.7-1.4, Ti/P = 0.15, and Ni/Ti = 0.1-2.0. The phase-formation field and parameters are determined for a new complex phosphate K4Ti3Ni(PO4)(6), which is isostructural to langbeinite. A single-crystal X-ray diffraction experiments is carried out for this phosphate (space group P2(1)3, a = 9.8247(10) angstrom).