HYDROTHERMAL AND SOLID-STATE SYNTHESIS, CRYSTAL DATA AND THERMAL-STABILITY OF MONOCLINIC AND RHOMBOHEDRAL LITHIUM ZIRCONIUM-PHOSPHATE

There is little or no controversy about the structure and crystal chem istry of sodium zirconium phosphate (NZP) family of materials except t he Li-member. The objective of this study was to establish the structu re and crystal chemistry of lithium zirconium phosphate by synthesizin g it under different conditions. A lithium zirconium phosphate, LiZr2( PO4)3 has been synthesized under hydrothermal conditions at 220-degree s-C. Its unit cell is monoclinic with 'a' ranging from 15.2 to 15.4ang strom, 'b' from 8.8 to 8.9angstrom, 'c' from 8.9 to 9.2angstrom and be ta from 124.8 to 125.3-degrees. This phase forms also by firing stoich iometric gels below 1080-degrees-C, above which temperature a rhombohe dral form of LiZr2(PO4)3 crystallizes with hexagonal axes of a = 8.856 angstrom and c = 22.205 angstrom.