Structural changes in the system Zn1-xCdxWO4, determined from single crystal data

The solid solution system Zn1-xCdxWO4 has been studied using single-crystal diffraction. Crystals, with sizes up to 1 cm in length and compositions in the range x=0.0-1.0, have been grown from Na2W2O7 fluxes. The composition x of the crystals deviates substantially from the composition in the flux. A linear relation between the composition x and the unit-cell parameters a and c has been found, but not for b and beta. The structure consists of six -coordinated W and Zn/Cd ions in oxygen octahedra, which forms the wolframi te structure type. The movement of the Zn/Cd ion in the octahedra is compar able with the effect of an increased pressure on the wolframite structure. The net result, when x increases, is that the wolframite structure deforms towards the scheelite structure type. The deformation of the octahedra in t he structure increases with increasing x.