In Situ Study of the Reaction Sequence in the Sol–Gel Synthesis of a (Ba 0.5 Sr 0.5 )(Co 0.8 Fe 0.2 )O 3−δ Perovskite by X‐Ray Diffraction and Transmission Electron Microscopy

Examination of the complexing citric acid/EDTA synthesis of (Ba 0.5 Sr 0.5 )(Co 0.8 Fe 0.2 )O 3−δ is presented by in situ X‐ray diffraction and transmission electron microscopy, which elucidate all intermediate phases and the formation of the perovskite structure for the first time.