Br2F7− and Br3F10−: peculiar anions showing μ2- and μ3-bridging F-atoms

Abstract

RbCl and CsCl react with BrF₃ yielding the corresponding decafluoridotribromates(III), MBr₃F₁₀ (M = Rb, Cs), which were structurally characterized for the first time. The Br₃F₁₀⁻ anion is surprisingly not linear but contains a μ₃-bridging fluorine atom and seems to be the first example of μ³-F bridging of Br atoms. The compounds are highly reactive and cannot be handled in glassware. As for the tetrafluoridobromates themselves, they are powerful oxidizers and thus suitable for the dry-chemical recycling of precious metals and additionally feature a significantly higher BrF₃ content.