Analysis of Metal Site Preference and Electronic Structure of Brownmillerite-Phase Oxides (A2B′ x B2−x O5; A = Ca, Sr; B′/B = Al, Mn, Fe, Co) by X-ray Absorption Near-Edge Spectroscopy

X-ray absorption near-edge spectroscopic (XANES) measurements of the Fe and Co K-edges for a series of Brownmillerite-type transition-metal oxides (A2B′ x B2−x O5; A = Ca, Sr; B′/B = Al, Mn, Fe, Co) have been made. In these compounds, the metal atoms are present in both octahedral and tetrahedral coordination environments. The spectra were interpreted with the aid of electronic structure calculations. Significant changes in intensity and energy …