Cheah, Melina C LKennedy, Brendan JamesWithers, RaymondYonemura, MasaoKamiyama, Takashi2015-12-130022-4596http://hdl.handle.net/1885/85080The synthesis and crystal structures of nine members of the rock-salt ordered double perovskites Sr2-xCaxCrNbO6 is presented. The crystal structures of the end members of the series Sr2CrNbO6 and Ca2CrNbO6 were refined using powder neutron diffraction data and are cubic in Fm over(3, -) m and monoclinic in P21/n, respectively, in both cases there being considerable anti-site Cr-Nb mixing. Variable temperature and/or composition studies suggest a direct first-order P21/n to Fm over(3, -) m transition, a suggestion supported by selected area electron diffraction studies. CrownKeywords: Crystal structure; Electron diffraction; Neutron diffraction; Phase transitions; Synthesis (chemical); Thermal effects; Chromium niobium oxides; Monoclinic; Rock-salt ordered; Sr2CaCrNbO6; Perovskite Chromium niobium oxides; Perovskite; Phase transition200610.1016/j.jssc.2006.04.0472015-12-12