ExperimentalThe crystal structure of P4WsO32 has been solved by three-dimensional single-crystal X-ray analysis. The refinements have been made in the space group P212121 with a = 5.285 (2), b = 6.569 (1), c = 17.351 (3)A, leading to R --0.058 and R w --0.071 for 967 independent reflections. The framework of this structure, built up of WO 6 octahedra and PO4 tetrahedra, can be described as ReOa-type slabs connected through PO 4 tetrahedra. This type of connection creates pentagonal tunnels in the [100] direction. Two sorts of empty cages are formed, limited by twelve or eighteen O atoms. The possibility of insertion of cations in the cavities of the structure and the existence of microphases P4W4nO 12n÷ 8 are discussed.

ChemInform Abstract Single crystals of the title compounds are prepared by annealing stoichiometric mixtures of BaCO3, (NH4)2HPO4, and NiO or CoCO3 (1.900 K, air; 2. evacuated silica tube. 1373 K, 8 h for (II) and 1170 K, 3 d for (I)). Both compounds are triclinic and belong to a new structure-type characterized by sheets built up by (M2O10)-groups formed by two edge-sharing MO6 octahedra and diphosphate groups (structure refinement in space group P1, cell parameters are given).

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