| Summary: | The crystal structures of Sr2CaMoO6 and Sr 2CaTeO6 have been determined at room temperature by neutron powder diffraction. Both compounds crystallize in the perovskite structure with a rock-salt ordered array of Ca2+ and M6+ cations (M = Mo, Te) on the six-coordinate sites (space group P21/n (no. 14); for M = Mo, a = 5.76228(7), b = 5.84790(7), c = 8.18707(9) Å, β = 90.194(1)°, for M = Te, a = 5.79919(9), b = 5.83756(8), c = 8.2175(1) Å, β = 90.194(1)°). Compositions in the solid solution Sr2CaMo1-xTexO6 have been synthesized and shown by X-ray diffraction to adopt the same ordered structure. The results are used in a discussion of the cation oxidation states in Ca 2FeMoO6 and to establish the similarity between the structural chemistry of hexavalent Mo and Te. © 2004 Elsevier Inc. All rights reserved.
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