Structure and vibrational properties of La2−xBixMo2O9 (0.05 ⩽ x ⩽ 0.4) oxygen ion conductors

Structure and vibrational properties of La2−xBixMo2O9 (0.05 ⩽ x ⩽ 0.4) have been studied using X-ray diffraction, infrared spectra as well as Raman spectra. It has been found that Bi doped samples have cubic symmetry with space group P213. The structure and lattice parameters of La2−xBixMo2O9 (0.05 ⩽ x ⩽ 0.4) are obtained from Rietveld refinement. The distorted nature of MoO4 tetrahedra is confirmed by bond-valence sums calculation. The effect of Bi lone pair is also confirmed by difference Fourier maps. From infrared and Raman analysis it is confirmed that different vibration modes arise from the vibration of molybdenum-oxygen bands. Mo-O bond lengths are also found to be independent of Bi-doping.