Synthesis and characterisation of the new oxyanion doped “0201–1201” type layered oxide, Sr4.5Fe2(S/Cr)0.5O9±δ

This work reports on an oxyanion containing Sr–Fe–O perovskite-related layered oxide system related to the “0201–1201” type material Sr4.5Cr2.5O9. Using solid state synthesis, we successfully incorporate SO42− and CrO42− to give Sr4.5Fe2(S/Cr)0.5O9±δ, with X-ray and neutron diffraction used to analyse the structure of these materials. Neutron diffraction experiments combined with 57Fe Mössbauer spectroscopy and X-ray absorption spectroscopy show not only the successful oxyanion incorporation, but also that these systems have the ability to accommodate excess interstitial anions. The stabilisation of these new phases highlights the potential to synthesise new perovskite-related compounds using oxyanion doping. [Display omitted] •Synthesis of new perovskite related intergrowth phases Sr4.5Fe2(S/Cr)0.5O9±δ.•Oxyanion (sulfate and chromate) incorporation is key to allowing the formation of these phases.•Neutron diffraction studies indicate incorporation of oxygen interstitials into “0201” type layers.