Structure determination of LiMoP₂O₇ from multiphase powder X-ray diffraction data

The crystal structure of LiMoP₂O₇ was determined from conventional powder X-ray diffraction at room temperature in the presence of MoP₂O₇, MoO₂ and Mo as impurities. Pattern decomposition was employed to eliminate complex contaminants prior to the Rietveld structure refinement. LiMoP₂O₇ crystallizes in the space group P2₁ with Z = 2, a = 4.8987 (3), b = 8.3912 (4), c = 7.0306 (4) Å, β = 109.327 (4)°, V = 272.71 ų. Final agreement indicators were R_p = 0.0589, R_wp = 0.0772, R_F = 0.054 and R_I = 0.080. The framework of the structure consists of corner-sharing MoO₆ octahedra and P₂O₇ groups, which form tunnels where the Li cations are located. The results give an example of analyzing a structure from a tetraphasic mixture using pattern decomposition in conjunction with the Rietveld refinement method.