The Xenon Fluorides Fluoride Donors and Acceptors

All three fluorides XeF (n = 2,4,6) are prepared by the action of elemental F2 on Xe under various conditions of temperature and pressure. Almost certainly, the mechanisms involve radical reactions of F atoms. We won t be discussing them here, but feel free to sharpen your skills with fishhook arrows by writing out some of them. 

The compounds act as both fluoride donors and acceptors. Thus, with tetramethylammo-nium fluoride in acetonitrile under rigorously anhydrous conditions, XeF4 forms the unique pentagonal-planar [XeFsJ anion  

Stepwise addition of fluoride to XeFg leads to the square-antiprismatic octafluoroxe-nate(VI) (XeFg ) anion, as shown below  

Octafluoroxenate salts are extraordinarily stable, even to temperatures above 400 C, proof that noble gas compounds are not just laboratory curiosities. 

Thermal decomposition of [XeF7] salts also leads to the [XeFg] anion, in yet another demonstration of the stability of the latter species  

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