Contributions to the investigation of inorganic non-stoichiometric compounds. 26

The mixed vanadium-tungsten oxide with the composition V16W9O65 (V/sub 0.64/W/sub 0.36/O/sub 2.60/) was prepared by chemical transport reactions. The dimensions of the tetragonal unit cell are a = 25.074 A; c = 3.714 A, determined by the X-ray-Guinier method. The probable space group is 14/mmm. The electron microscopical investigation directly reveals the block structure of the new compound. The block are made up of [5 x 5 x infinity] corner sharing M-O-octahedra. Other unusual block sizes are observed as defects. The blocks are connected by common corners like in the related compound (V/sub 0.65/W/sub 0.35/)2O5 with [4 x 4 x infinity] blocks. (author)