Dipyridiniomethane cis-Dibromotetrafluoroosmate(IV), cis-[(C₅H₅ N)₂CH₂][OsBr₂F₄]

The title compound is an AB-type salt with a completely ordered anion sublattice. Because of the strong trans influence of the Br ligands, both Os-Br bonds, of 2.466 (1) and 2.468 (1) Å, are shortened compared to those reported for K₂[OsBr₆] (2.51 Å). However, only one of the two F ligands coordinated trans to a Br ligand exhibits a longer Os-F distance [1.968 (4) Å] than those along the symmetrically coordinated F-Os-F axis [1.930 (4) and 1.929 (4) Å].

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