As we have indicated above, by using the sol gel synthesis method, with the procedure described in the experimental section, a 6H-BaFeO2.78 phase is obtained. The choice of sol gel method is not by chance. First, it is one of the few methods in which oxygen content can be controlled while being reproducible. Moreover, the particle size of the asprepared products can be kept within the nanometer range in contrast to solid-state reaction. Two additional oxidation processes were applied to the BaFeO2.78 phase to obtain BaFeO2.90 and BaFeO2.96.