Structural and thermal properties of the phase V/sub 1-x/Cr/sub 2x/3M/sub x/3O2, M = W6+ or Mo6+

The V/sub 1-x/Cr/sub 2x/3/M/sub x/3/O2, where M = W6+ or Mo6+, solid solutions have been prepared and studied by x-ray diffraction and DTA methods. Complete crystalline solubility has been found in the system VO2--Cr2WO6. Four phases with related structures have been reported for V/sub 1-x/Cr/2x/3/W/sub x/3/O2, at room temperature, they are respectively monoclinic (M1), monoclinic (M2), rutile (R) and trirutile (TR). Only 33 mole percent Cr2MoO6 dissolves in VO2. Two structural transitions from the monoclinic (M1) to the monoclinic (M2) and from the monoclinic (M2) to the rutile (R), have been identified for V/sub 1-x/Cr/sub 2x/3/Mo/sub x/3/O2. It is interesting to report that the T/sub c/ first decreases, and then increases, with increasing x in both the systems