Neutron and X-ray diffraction study on polymorphism in lithium orthotantalate, Li3TaO4

Reinvestigation of β-Li3TaO4

“…Twofold axes pass through the midpoints of one subset of TaO 6 shared edges, while inversion centres are to be found on the other shared TaO 6 edges, as well as on shared LiO 6 octahedral edges. Martel & Roth (1981) observed two phase transitions in the Li 3 TaO 4 system using differential thermal analysis, one at 1173 K and a second at around 1700 K. Zocchi et al (1983) ascribed the low temperature -form to a cell of dimensions a = 8.500 (3), b = 8.500 (3), c = 9.3443 (3) A Ê , = 117.05 (2) and space group C2/c. The high temperature -form was ascribed to a = 6.027 (2), b = 6.004 (2), c = 12.822 (4) A Ê , = 103.60 (2) and space group P2.…”

“…The high temperature -form was ascribed to a = 6.027 (2), b = 6.004 (2), c = 12.822 (4) A Ê , = 103.60 (2) and space group P2. Subsequently the -phase was revised to P2/n (Zocchi et al, 1984). Roth (1984) suggested that there may be several intermediate polymorphs, including both disordered and metastable variants, though as yet these remain uncharacterized.…”

Low-temperature sintering and microwave dielectric properties of Li3MO4 (M=Ta, Sb) ceramics

“…[15]. The Li 3 SbO 4 belongs to a monoclinic structure with space group P2/c (13) as reported by Skakle et al [16].…”

X-Ray and Ultraviolet Luminescence of Li3Ta1−xNbxO4 Prepared by Flux Synthesis and Characterization of a New High Efficiency X-Ray Phosphor

“…The synthesis of the low-temperature form of Li TaO by conventional solid-state techniques, used by Zocchi et al (4), involves reacting lithium metatantalate and lithium carbonate. Following their procedure, LiTaO and Li CO were ground together and heated for 20 hours at 7003C, reground and heated for 120 hours at 8003C, and then reground and heated for 17 hours at 10003C to obtain phase pure material.…”

“…Prior to this work, the two end-member compositions had been prepared using traditional solid-state methods (4,5) and only a brief examination of their UV-excited luminescence properties had been performed (5). This paper focuses on the characterization of the luminescence properties of the entire range of compositions under both X-ray and UV-excitation.…”