ISODISTROTLaMTeO (M = Ga and Mn): the critical role of electronic configuration and cation ordering in crystal structures.

In this work, PbSbO-type oxides LaMTeO (M = Ga and Mn) were synthesized and structurally characterized by Rietveld refinements against high-resolution X-ray powder diffraction data. The Ga/Te partial ordering within the honeycomb-like two-dimensional [GaTeO] anionic layer leads to the loss of the inversion center between Ga and Te; however the inversion center on the 3̄-roto-inversion axis is preserved, thereby resulting in a 2-fold PbSbO-type superstructure by doubling the -axis associated with a structural symmetry descending from the original 3̄1 to 3̄1 symmetry. In contrast, LaMnTeO (2/) adopts a monoclinically distorted 4-fold superstructure with lattice dimensions of ≈ , ≈ √3, ≈ 2, where and represent the lattice parameters of trigonal PbSbO.