Crystal structure of R10Mo6O33 (R = Nd, Pr) from 3 K to 973 K by neutron powder diffraction

Oxygen ionic conductors, R10Mo6O33 (R = Nd, Pr), were investigated by neutron powder diffraction in the wide temperature range from 3 K to 973 K. The Rietveld analyses and peak profile examination confirmed that there are no structural phase transitions in whole temperature range, keeping a cubic structure. The nuclear density distribution calculated by maximum entropy method and the Bond Valence Sum mapping analysis shows that a possible diffusion pathway connects the neighboring 48i oxygen ions at general positions. These results are consistent with the previous results of a one-particle Coulomb potential calculation and electric conductivity measurements.