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 oxygen stoichiometry at 850 degreesC. The crystal structure was determined using powder X-ray diffraction, electron diffraction, and high-resolution electron microscopy. Sr2ScBiO6 has a perovskite-derived pseudocubic face-centered 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 parameters 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 compound. (C) 2001 Academic Press.