LITHIUM VANADIUM CHLORIDES PHASE-TRANSITION, CRYSTAL-STRUCTURE OF THEMIXED-VALENCE COMPOUND LI1.3V1.2CL4

Single crystals of the mixed valence compound Li1.3V1.2Cl4 were grown by vapor-phase transport of Li2VCl4 using VCl3 as transporting agent. They crystallize in the cubic space group <F(4)over bar 3m> (Z = 8) wi th Li(1) and vacancies square at the tetrahedral 4a and 4c sites, and Li(2) and V (occupation factors: 0.397(4) and 0.603(4)) at the octahed ral 16e site, respectively, as revealed by X-ray single-crystal struct ure determination (a = 1035.7(1) pm, 162 unique reflections, R-w = 1.6 %). Phase transition of likewise MgCr2O4-type Li2VCl4 to a Zr3S4-type high-temperature polymorph above 600 K was revealed by high-temperatur e X-ray experiments and DSC measurements. (C) 1997 Elsevier Science Lt d.