Preparation and characterization of gold pentafluoride

Abstract

Gold pentafluoride, AuF₅, has been prepared by the termal decomposition of [O₂][AuF₅]in vacuo. Some reformation of [O₂][AuF₆] occurs on the surface, suggesting that vapour transport is via AuF₅ and O₂F radicals since no evidence could be found for AuF₆. The sublimate also contains AuF₃, a decomposition product. More pure AuF₅ can be separated from the mixture by a second sublimation leaving AuF₃ as a residue. Each of the species AuF₅, [O₂][AuF₆], and AuF₃ is distinguishable by its mass spectrum and Raman spectrum. AuF₃ and [O₂][AuF₆] are crystalline, whereas AuF₅ prepared by double sublimation is amorphous. It is diamagnetic, and the Rman spectrum indicates that AuF₅ is a fluorine-bridge polymer. AuF₅ reacts with XeF₂ in anhydrous HF solution to form an insoluble adduct isomorphous with [Xe₂F₃][IrF₆].