Uschcapivska T. Synthesis, structure, properties of mono- and polyvalent metal phosphates.

The dissertation is devoted to synthesis and research of the complex phosphates received under various conditions of their formation. Influences of trivalent metals (MІІІ-Al, Cr, Fe, In, Sc, Y) on orthophosphate phase formation has been established in system K2O-P2O5-TiO2 in the environment of the fused phosphates of alkaline metals and at hydrothermal interaction in a wide interval of К/P and MІІІ/Ті ratio. Areas and conditions of formation heterovalent replaced orthophosphates on mechanism М2IV®MIII+MV in phosphate melts and at solid state interaction for systems Na2O-P2O5-Fe2O3-MV2O5 (МV-Nb, Ta) and МІ2O-P2O5-Fe2О3-Nb2O5 (МІ-Li, Na, K) have been determined. Influence of a components ratio in initial systems, temperatures, time of synthesis for structure of formed phosphates have been considered. Researches of conductivity- temperature dependence has been carried out for ceramic samples of general structure Na3-2xFe2-xNbx(PO4)3 (х=0-1,5). Crystals NaFeNb(PO4)3 have been investigated by X-ray structure analysis. There have been developed bases of synthesis and growing of monocrystals of complex phosphates the structure of which simultaneously includes alkaline and polyvalent metals (the latter in different degrees of oxidation).