Calculation of cation migration channels in crystals with sсheelite-type structures

Chem. Met. Alloys 12 (2019) 61-70

https://doi.org/10.30970/cma12.0389

V.N. SHEVCHUK, I.V. KAYUN

A stereo-atomic crystal structure analysis was applied to AWO₄ (A = Ca, Pb) crystals. The program package TOPOS was used for the calculations. 3D migration paths for the W ions in the AWO₄ compounds at different temperatures were visualized. Peculiarities of the migration paths and the conditions for possible ionic conductivity in crystals with scheelite-type structures were considered. The influence of the introduction of Eu³⁺ ions on the migration path of the W ions in CaWO₄ was analyzed. The temperature dependencies of the lengths of particular elementary channels and their evolution with variations of the unit-cell parameters of the crystals were considered in connection with the conditions of the synthesis of the compounds.

Framework of WO₄^2--complexes and three possible migration paths of the W ions in PbWO₄ with scheelite-type structure.

Keywords

AWO₄ (A = Ca, Pb) / CaWO₄:Eu³⁺ / TOPOS / Cation migration / Migration map / Scheelite