M. Saadi

Carnotite analogues: synthesis, structure and properties of the Na1–xKxUO2VO4 solid solution (0 ⩽x⩽1)

Crystal structures of synthetic K2(UO2)2V2O8(carnotite) and Na2(UO2)2V2O8 have been refined using single-crystal X-ray diffraction. The alkali-metal ions were shown to lie between [(UO2)2V2O8]∞, layers. A continuous solid solution was obtained between these two compounds. Both compounds and the solid solution have high ionic conductivity. For example, K and Na compounds have conductivities at 500 °C of 9.2 × 10–5 and 1.7 × 10–4 S cm–1, respectively, and activation energies of 0.57 and 0.52 eV.