REGARDING THE EXISTENCE OF THE BI2W1-XCUXO6-2X (0.7-LESS-THAN-OR-EQUAL-TO-X-LESS-THAN-OR-EQUAL-TO-0.8) SOLID-SOLUTION

A new family of oxide-ion conductors derived from Bi2WO6 and prepared by substitution of Cu-II for W-VI was recently described by Sharma et al, (J. Mater. Chem., 1994, 4, 705). Attractive performances were obtained with the Bi2W1-xCuxO(6-2x) (0.7 less than or equal to x less than or equal to 0.8) solid solution. Our experiments performed on the x=0.75 compound are in agreement with the synthesis of a 7Bi(2)O(3) . 2WO(3)-Bi2CuO4-5CuO mixture rather than a new solid solution.