Powder X-ray diffraction (XRD) patterns were collected using Cu Kα monochromatic radiation (λ = 1.54056 Å) at room temperature on a Panalytical X'PERT PRO MPD diffractometer equipped with a germanium (111) primary beam monochromator and X'Celerator fast detector. Diffraction data were analyzed by the Rietveld method using the FullProf program The average cationic composition was determined by Energy Dispersive X-ray Spectroscopy (EDS). The average oxidation state of iron was determined by a redox titration method, and, from this, the oxygen content is obtained. Samples were dissolved in HCl (6N) with an excess of Mohr salt. The Fe 2+ ions react with the possible Fe 4+ present in the sample, leading to Fe 3+ ions. The amount of remaining Fe 2+ ions was determined by titration with a 0.1 N K2Cr2O7 solution.