Synthesis and crystal structure of Sr2ScBiO6

A new complex oxide Sr2ScBiO6 was synthesized by a solid state reaction in air. The compound is stable up to 1150 degreesC and acquires the desired ox ygen stoichiometry at 850 degreesC. The crystal structure was determined us ing powder X-ray diffraction, electron diffraction, and high-resolution ele ctron microscopy. Sr2ScBiO6 has a perovskite-derived pseudocubic face-cente red unit cell (a = 8.1816(3) Angstrom) and a rock-salt ordering of Sc3+ and Bi5+ over the B positions. Electron microscopy investigation reveals that the real structure is of the La2NiRuO6 type, monoclinic with cell parameter s a approximate to b = aper root2 approximate to 5.785 Angstrom, c = 2a(per ) approximate to 8.182 Angstrom, and P2(1)/n space group. The structure can be described by an a(+)b(-)b(-) system of the BO6 octahedral tilting. The presence of numerous twin domains is a characteristic feature of this compo und. (C) 2001 Academic Press.