Structure of the metastable cubic B1 phase of the La2Mo2O9 single crystal

The structure of the metastable B-1 phase of the La2Mo2O9 single crystal is investigated using X-ray diffraction. It is established that the crystal structure of the compound under investigation is described by the cubic unit cell with the parameter a = 7.158(5) A..., which makes it possible to index approximately 84% of the reflections measured for this single crystal. The structure of the metastable cubic B-1 phase is characterized by a local lowering of the symmetry for the La and Mo atoms, which are displaced from their positions on the threefold axis, thus forming three sites around it with an occupancy of 0.333(2). The O(1) atom in the structure of the metastable cubic B-1 phase remains in the 4a position on the threefold axis but occupies it by only 86%. The O(2) and O(3) atoms located in a general position occupy their own sites with occupancies of 0.77(2) and 0.35(2), respectively. The final R factor of the refinement of this structural model is 2.52%.