Synthesis and characterization of a new magnesium molybdates Tl1.85M0.15Mg2(MoO4)3 (M = K, Rb) with a langbeinite type structure

Grossman, V.G., Molokeev, M.S., Bazarov, B.G., Bazarova, J.G.// Solid State Sciences, 142, art. no. 107249.//

https://doi.org/10.1016/j.solidstatesciences.2023.107249

In this work we have successfully synthesized pure phases of Tl_1.85M_0.15Mg₂(MoO₄)₃ (M = K, Rb) langbeinite powders using the solid-state reaction method. Structural characterization was carried out via the Rietveld method on the X-ray powder diffraction data. The following unit cell parameters are calculated for Tl_1.85K_0.15Mg₂(MoO₄)₃: a = 10.68509(16) Å, V = 1219.93(6) Å³, and for Tl_1.85Rb_0.15Mg₂(MoO₄)₃: a = 10.69463(9) Å, V = 1223.20(3) Å³. The electrical conductivity was studied by impedance spectroscopy in the [473–1010 K] temperature range and results show that the Tl_1.85M_0.15Mg₂(MoO₄)₃ (M = K, Rb) were ionic solid electrolyte conductors. Results also show that Tl_1.85K_0.15Mg₂(MoO₄)₃ has the highest electrical conductivity.