Influence of the structure of CrPO4 on the formation of CrVxP1−xO4 solid solutions and their colour

Abstract

CrVxP1-xO4 (0 <= x <= 1) compositions were synthesized via the chemical co-precipitation method. At 600 degrees C, the detected crystalline phase is monoclinic CrVO4 when x >= 0.7. At 800 degrees C, two isostructural phases with orthorhombic symmetry are detected. At this temperature, beta-CrPO4 is present when x <= 0.7 and orthorhombic CrVO4 when 0.1 <= x <= 0.9. The two orthorhombic phases, beta-CrPO4 and CrVO4, are stable at 800 and 1000 degrees C. At 1200 degrees C, the major crystalline phase is the alpha-CrPO4 polymorph when x <= 0.3. This phase is not present when x >= 0.7.