Nonstoichiometry of the perovskite-type solid solution La0.9Ca0.1Cr1−yAlyO3−δ

Nonstoichiometry of the perovskite-type solid solutions La0.9Ca0.1Cr1−yAlyO3−δ was studied by high-temperature gravimetry under controlled P(O2) atmospheres of 1–10− 23 bar at 1073–1273 K. The observed data were described by a regular solution-like model for the randomly distributed defects of VO¨, CrCr., CaLa,, and AlCrX. With the increase in y, VO¨ formation becomes much easier. For y > 0.8, some fraction of CaLa, becomes surrounded only by AlCrX and VO¨ remains around such CaLa, up to high P(O2) to reduce the maximum oxygen content below 3.000.