Evolution of Crystallographic Phases in (Sr1-xCax)TiO3 with Composition (x)

A new complex oxide Sr2ScBiO6 was synthesized by a solid state reaction in air. The compound is stable up to 1150°C and acquires the desired oxygen stoichiometry at 850°C. The crystal structure was determined using powder X-ray diffraction, electron diffraction, and high-resolution electron microscopy. Sr2ScBiO6 has a perovskite-derived pseudocubic facecentered unit cell (a=8.1816(3) ?) 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~b=apersquare root=radical sign2~5.785 ?, c=2aper~8.182 ?, and P21/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.