The crystal structure of trifluoroxenon(IV) hexafluorobismuthate(V): the fluoride-acceptor strength of bismuth pentafluoride

Abstract

The crystal structure of [XeF₃][BiF₆] has been determined from three-dimensional X-ray counter data. Crystals are triclinic with a= 5.698(3), b= 7.811(3), c= 8.854(4)Å, α= 99.45(5), β= 110.09(5), γ= 92.84(5)°, U= 362.7 ų, Z= 2, and D_c= 4.69 g cm^–3. The structure has been refined in the space group P to a final conventional R′ of 0.097 for 1 238 independent reflections. The structure consists of [XeF₃]⁺ and [BiF₆]^– ions with a close contact of 2.25(2)Å between the xenon atom of the T-shaped cation and fluorine atom of the octahedral anion. The bridging fluorine is shown to be more strongly associated with the xenon in [XeF₃][BiF₆] than in [XeF₃][SbF₆], indicating that BiF₅ is a weaker fluoride acceptor than SbF₅.