B. Muktha

The crystal structure of 1,2,3,4,6-penta-O-benzoyl-\alpha-D-mannopyranose: observation of C-H...\pi interaction as a surrogate to O-H...O interaction of a free sugar

The crystal structure of the title compound was determined by X-ray crystallography. The compound crystallized in the orthorhombic space group P2(1)2(1)2(1) with four molecules in the unit cell with a=9.170(2), b=9.873 (2), c=38.831(8) A. The structure was refined to a R index of 0.041 for 7907 independent reflections. The mannopyranose unit adopts a distorted 4C1 conformation. The structure depicts unique network of C-H...pi interactions, very closely resembling the pattern of O-H...O interactions in free sugars. This intriguing and rare observation points to a notion that the supramolecular organization pertaining to a sugar is in-built in the pyranose ring itself.

Crystal structure and ionic conductivity of a new bismuth tungstate, Bi3W2O10·5

The compound Bi3W2O10.5 was synthesized by the solid-state technique from Bi2O3 and WO3 in stoichiometric quantities. Single crystals were grown by the melt-cooling technique and the crystal structure was solved in the tetragonalI4/m space group witha = 3.839 (1) Å,c = 16.382 (5) Å,V = 241.4 (1) Å3,Z = 4 and was refined to anR index of 0.0672. The structure represents a modification of the Aurivillius phase and consists of [Bi2O2]2+ units separated by WO8 polyhedra. a.c. impedance studies indicate oxide ion conductivity of 2.91 10−5 Scm−1 at 600°C.