The electronic structure and chemical bonding in the Sr2Fe2O5 strontium ferrate were investigated in the framework of the ab initio linear-muffin-tin-orbital tight-binding representation and extended Hückel calculations. Models of defect formation (O vacancies and anti-Frenkel defects) in the brownmillerite structure were considered. A model of ion transfer in strontium ferrate was proposed reasoning from the results of the calculations.

Specific Features of the Formation of Oxygen Defects in the SrFeO2.5 Ferrate with a Brownmillerite Structure. V.M.Zaĭnullina, I.A.Leonidov, V.L.Kozhevnikov: Physics of the Solid State, 2002, 44[11], 2063-6