New CaCrO3d superstructure phases (d ¼ 0.33, 0.4, and 0.5) have been discovered through ‘soft’ low temperature reduction of the perovskite CaCrO3 made at ‘hard’ high pressure–temperature conditions. Their structures form a related series based on stacking of octahedral and tetrahedral chromium oxide layers.
Hard–soft synthesis of a new series of vacancy-ordered perovskites, CaCrO 3− δ
