RUTILE SUPERSTRUCTURE OF SB0.9V1.1O4

The structure of Sb0.9V1.1O4, antimony vanadium oxide, has been studie d by powder X-ray diffraction, electron diffraction and high-resolutio n electron microscopy (HREM). The X-ray powder diffraction pattern sho wed only basic ruble reflections [a(r) = 4.6085 (1), c(r) = 3.0867 (1) Angstrom] and the basic rutile structure was refined using the Rietve ld method. A ruble superstructure was revealed when the sample was stu died by electron diffraction. The electron diffraction patterns were i ndexed on the unit cell a = 2(1/2)a(r), b = 2(1/2)b(r), c = 2c(r). Its space group, I4(1)md, was determined by means of convergent-beam elec tron diffraction (CBED). A structural model based on alternating catio n ordering along c in the chains of edge-sharing octahedra is proposed and its electron diffraction patterns and HREM image are calculated a nd matched with the experimental ones.