In this sense we want to highlight that our redox study on BaFeO3- samples with small particle size, heating up to 550 ºC and working in different atmospheres, vacuum and air, extends the anionic compositional range in which the basic 6H structure remains to δ= 0-0.37 significantly wider than that reported by these authors allowing to evidence, for the first time, the existence of a lowering symmetry phase transition from hexagonal to orthorhombic (Cmcm) symmetry that takes place when the oxygen composition is less than about 2.8 ( close to 0.2) up to 2.63 ( close to 0.37).