Multistep synthesis of the SrFeO2F perovskite oxyfluoride via the SrFeO2 infinite-layer intermediate

The SrFeO2F oxyfluoride was prepared through a low temperature, multistep synthetic route starting with the SrFe03, perovskite via the SrFeO2 infinite layer intermediate phase. In the final step SrFeO2F was formed by reacting SrFeO2 with XeF2 at 150 degrees C. In spite of utilizing an intermediate with layered ordering of oxygen vacancies, disordered SrFeO2F was synthesized. Rietveld refinement of synchrotron powder diffraction data did not reveal any signs of tetragonal distortion predicted by DFT calculations for SrFeO2F with layered O/F ordering. Significantly, the magnetic properties observed are drastically different from those reported earlier in the literature indicating that the properties of O/F disordered phases depend on the degree of short range ordering. Mossbauer spectroscopy measurements revealed the predominance of cis fluorine configuration in SrFeO2 polyhedra, confirming a difference in local Fe coordination in comparison with O/F disordered SrFeO2F. (C) 2013 Elsevier B.V. All rights reserved.