Amor Haddad

KNb4AsO13: Preparation et structure cristalline

Abstract KNb 4 AsO 13 : Mr = 693,64 crystallizes in the orthorhombic system, space group: Cmcm , a = 10,477(4), b = 10,312(4), c = 10,006(4)A, Z = 4. The crystal structure was refined from 760 independent reflections. The final R index and weighted R w index are 0,026 and 0,030, respectively. The three-dimensional network is constituted of infinite chains (NbO 6 NbO 6 AsO 4 ) n parallel to the a axis and linked to each other by pairs of edge-sharing octahedra. Each pair links together four infinite chains. The potassium ions occupy interconnected cavities parallel to the c axis with an occupancy rate equal to 50%.

Synthesis and crystal structure of K3Sb4BO13

AbstractK3Sb4BO13, Mr = 823.11 g.mol−1, crystallizes in the triclinic system, space group P

A Novel Defect Pyrochlore: (Na1.08VV0.43SbIII0.14)(SbV2O6)O′0.84. Preparation and Crystal Structure

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Synthèse et structure cristalline de Rb5VONb14O38

, Z = 2. The lattice parameters are a = 7.133(1) Å, b = 7.232(1) Å, c = 13.259(2) Å, α = 82.00 (1)°, β = 99.77(1)° and γ = 117.08(1)°, V = 598.7(2) Å3, Dx = 4.566 Mg m−3. The final R index and weighted Rw index are 0.0251 and 0.0623, respectively. The three-dimensional network of the title compound is constituted by layers (Sb3O9)n, similar to that of hexagonal bronze of Magneli. These layers are linked together, in the c direction, alternatively by edge-sharing pairs of SbO6 octahedra and BO3 triangles. This framework has interconnected tunnels, running approximately along the a and b directions, in which the K+ ions are located.