Crystallographic and spectroscopic characterization of LnFeTeO6 (Ln = La, Pr, Nd, Sm) materials

Four mixed oxides of composition LnFeTeO6 (with Ln = La, Pr, Nd, Sm), belonging to a superstructure of the PbSb2O6 structural type, have been prepared by solid state reactions and their unit cell parameters determined by X-ray powder diffractometry. The infrared and Raman spectra of these materials were also recorded and briefly discussed, on the basis of a site-symmetry analysis. The 57Fe-Mössbauer spectra show that the FeIIIO6 octahedra present in these materials are not greatly distorted.

Research highlights▶ LnFeTeO6 (Ln = La, Pr, Nd, Sm) materials belong to a PbSb2O6 superstructure. ▶ IR and Raman spectra are dominated by TeO6 vibrations. ▶ Te–O bonds are relatively weak.▶ FeIIIO6-polyhedra are scarcely distorted.