[010]H projection (see Figure ), evidences that the formation of oxygen vacancies in BaFeO2.96 does not break the -cchcch-packing sequence along the c axis of the 6H polytype. It is worth mentioning that, although the hexagonal packing is kept, marked differences in the intensity of the contrasts along the c axis are observed when comparing the image recorded at room temperature (pristine sample) with the one recorded at 300 ºC, this suggests that the oxygen vacancy ordering involves certain displacement of the cationic sublattices.