Acta Cryst. (2007). E63, i16-i18  [ doi:10.1107/S1600536806053864 ]

Powder diffraction study of Ba(NH₄)₄(PO₃)₆

L. S. Ivashkevich, A. F. Selevich, A. I. Lesnikovich and A. S. Lyakhov

Abstract: The crystal structure of barium tetraammonium poly{hexakis[phosphate(V)]} was solved by direct methods from laboratory X-ray powder diffraction data collected at room temperature. The trigonal crystal structure is isostructural with BaCs₄(PO₃)₆. The Ba²⁺ cation and one of the N atoms lie on a threefold axis, whereas all remaining non-H atoms are in general positions. The Ba²⁺ cation is bonded to nine O atoms from three polyphosphate chains to form a distorted tricapped trigonal prism as coordination polyhedron. Links between the polyphosphate chains and the Ba²⁺ ions result in a three-dimensional network, with tunnels and cavities filled by ammonium cations.

Online 23 December 2006

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