Crystallographic Properties of Ca2Fe2O5. Difference in Crystallographic Properties of Brownmillerite-like Compounds, Ca2Fe2O5 and Sr2Fe2O5, at Elevated Temperatures

Abstract High-temperature X-ray diffraction analysis has revealed that Ca2Fe2O5 remains in the original brownmillerite-like form up to ca. 1100 °C, whereas Sr2Fe2O5 changes in crystal structure from brownmillerite to anion-deficient perovskite, without a change in oxygen content, above 700 °C.