Crystallographic Studies of Cesium Tetrafluorobromates(III)

This article describes CsBr2F7 (1) which has been obtained in the form of colorless single crystals. Shown by the X-ray diffraction on single crystals its Br2F7− anion is neither planar nor is its Br−μ-F−Br unit linear, as previously deduced from Raman spectra. Also a regular tetrafluorobromate CsBrF4 (2) has been obtained in the form of a colorless powder. Compound 2 can also be obtained from compound 1 by evacuation. The crystal structure of CsBrF4 (2) has been elucidated by the Rietveld refinement on its X-ray powder pattern.