Metastable tetragonal phase CdWO₄ nanoparticles synthesized with a solvothermal method

CdWO₄ has only previously been reported in the monoclinic, or wolframite, phase. Here we report the first metastable, tetragonal or scheelite, CdWO₄ nanopowder. The tetragonal CdWO₄ was synthesized by a propylene glycol solvothermal method. The scheelite phase is stabilized by a combination of high surface area and surface complexation by the propylene glycol. The CdWO₄ is stable at 1 bar to 300 °C, and converts back to the monoclinic wolframite phase between 300 and 500 °C. The nanopowder exhibits cubic morphology and the average particle size of the nanopowder is around 50 nm.