Ogorodnyk I. Complex phosphates of titanium, zirconium and hafnium

The thesis is devoted to synthesis of complex phosphates of titanium, zirconium or hafnium in potassium and cesium phosphate melts, and determination of their structure-composition relations. Regions and conditions of formation of langbeinite-type Ti-, Zr- and Hf-containing phosphates were determined. The applied synthetic approaches allowed crystal growth of Zr- and Hf-containing phosphates and preparation of more than 100 compounds ( 85 firstly). The crystallographic criteria were found by structure analyses: the features of metal distribution over framework positions. The possibilities of preparation of langbeinite-like phosphate frameworks formed by a variety of elements and the stabilization of different oxidation states of metals by crystalline matrix were suggested. The relations between structure and IR-, EPR- and electron spectra were determined. Principle possibility of the usage of langbeinite-type phosphates as matrices for immobilization of radioactive isotope waste were suggested (SynRock strategy).