CRYSTAL-STRUCTURE OF LI2WO4LL - STRUCTURE RELATED TO SPINEL

Li2WO4II, synthesized at 3 kbar and 630°C, has tetragonal symmetry, I41 amd, a = 11.954(2) and c = 8.410(1)Å, Z = 16, Dcalc = 5.78 g cm-3. The structure was determined by countermeasuring 469 independent reflections from a single crystal and was refined up to R = 0.032 by the full-matrix least-squares method. It is based on cubic closest packing of oxygen atoms and is closely related to the β-phase structure of Mg2SiO4. W and Li(2) are in octahedral sites and Li(1), in tetrahedral sites. Four Li(1)O4 tetrahedra form a Li4O12 group, WO6 and Li(2)O6 construct a octahedral double chain along the a axis, and four WO6 octahedra build a W4O16 group by sharing their octahedral edges. © 1979.