Homologous Series of SrCoO(3n−1)/n Perovskites Obtained Through Br2 Oxygenation of SrCoO2.5

Starting from brownmillerite SrCoO 2.50, a series of SrCoO 3−δ samples with different oxygen contents up to 3 − δ = 2.87 was successfully prepared using Br 2 in CH 3 CN/H 2 O medium as an oxidant. Six different phases, including the precursor phase, were identified depending on the oxygen content. Four of the phases have been known from earlier studies, that is, SrCoO 2.50, SrCoO 2.75, SrCoO 2.80, and SrCoO 2.87 (the latter three obtained through electrochemical and high-pressure high-temperature oxidation techniques) representing, respectively, the n = 2, 4, 5, and 8 members of the SrCoO (3 n −1)/ n homologous series, whereas signatures for the n = 6 and 7 members were revealed here for the first time.