Redetermination of beta-Ba(PO3)(2)

In comparison with the previous structure determination of the beta-modification of barium catena-polyphosphate that was based on Weissenberg film data [Grenier et al. (1967). Bull. Soc. Fr. Mineral. Cristallogr. 90, 24-31], the current CCDdata- based redetermination reveals all atoms with anisotropic displacement parameters, standard uncertainties for the atomic coordinates, and the determination of the absolute structure. Moreover, a much higher accuracy in terms of the bond-length distribution for the polyphosphate chain, with two shorter and two longer P-O distances, was achieved. The structure consists of polyphosphate chains extending parallel to [100] with a periodicity of two PO4 tetrahedra. The Ba2+ cations are located between the chains and are surrounded by ten O atoms in the form of a distorted coordination polyhedron, with Ba-O distances ranging from 2.765 (3) to 3.143 (3) angstrom, also reflecting the higher precision of the current redetermination.