Cerium, iron and bismuth-containing molybdovanadate solid solutions with scheelite-type structure

Bi1−x/3Øx/3(V1−xMox)O4 (x from 0 to 0.75 in steps of 0.15), Bi(1−x/3)+yØ(x/3)−y(V1−xMox−yFey)O4 (x=0.45; 0.00≤y≤0.15 in steps of 0.05), Bi1−x/3Ø(x/3)−yFey(V1−xMox−yFey)O4 (x=0.45; 0.00≤y≤0.15 in steps of 0.05), Bi1−x/3Ø(x/3)−yCey(V1−xMox−yFey)O4 (x=0.45 and 0.60; 0.00≤y≤x/3, in steps of 0.05), and Ce1−x/3Øx/3(V1−xMox)O4 (x from 0 to 0.60 in steps of 0.15) solid solution systems (Ø=cation vacancy in the eight-coordinated sites, tetrahedrally coordinated cations in parenthesis) have been prepared by coprecipitation and final firing at 873 K. Structural characterization has been performed by lattice parameter measurements. Optical and magnetic properties have also been investigated. The X-ray analysis showed that the great majority of materials are monophasic with tetragonal scheelite-type structure. The correlation between unit cell volume and metal composition shows the effect of the cation and vacancy substitution on the unit cell lattice, which is interpreted in terms of the different ionic radii of the interchanging metal ions and of filling up or creation of cation vacancies.