Structural Chemistry of a New 10H Hexagonal Perovskite: BaMn0.4Fe0.6O2.73.

A new 10H polytype has been stabilized in the BaMn1–xFexO3–y system with the composition BaMn0.4Fe0.6O2.73. The anionic composition has been established by a reduction and re-oxidation cycle in the stability range of this phase. The structural characterization was carried out by high-resolution electron microscopy (HREM), electron diffraction, and X-ray diffraction. The structure is closely related to the ideal (hch′ch)2 10H polytype with two oxygen-deficient hexagonal (h′) BaO2–y layers per unit formula. This framework gives rise to blocks of three octahedra sharing faces linked by corners to two corner-sharing tetrahedra.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007)