Both are used as components of ionic liquids and as weakly coordinating anions in the study of highly reactive cations.
This forces HF to act as a Brønsted–Lowry base, producing the solvated protons which account for the mixture's superacidity: While fluoroantimonic acid is often depicted according to the above - roughly analogous to the autooxidation of water into hydronium and hydroxide - this reaction is an oversimplification.
Fluorination of antimonate[2] and of antimony trioxide (with hydrogen peroxide as an oxidant)[3] with HF as a solvent can yield fluoroantimonates from metal fluoride salts.
As weakly coordinating anions, fluoroantimonates can be used to study highly reactive cations.
Examples include hydronium (crystallised from magic acid as the undecafluorodiantimonate),[4] fluoronium (directly crystallised from fluoroantimonic acid as the undecafluorodiantimonate),[5] noble gas-noble metal cations such as tetraxenonogold(II) (as the undecafluorodiantimonate)[6] and xenonomercury(II) (as a mixed salt of hexafluoroantimonate and undecafluoroantimonate),[7] and derivatives or complexes of platinum group metals.