Synthesis, structural characterization, thermal stability and electrical properties of the new phases MIGa(CrO4)2 (MI=Na, K, Rb)
New phases of composition MIGa(CrO4)2 (MI=Na, K or Rb) have been synthesized by solid state reaction in air. The crystallograhic data of the three compounds have been refined by the Rietveld method. They all show a layer structure, the layer being formed of GaO6 octahedra linked to CrO4tetrahedra by sharing corners. Alkali metal ions lie in the interlayer space. The three compounds are thermally stable up to 300 °C, but above this temperature they decompose evolving oxygen. Impedance measurements show that they are ion conductors, the ionic conductivity being highest for the Na compound.