Conceptual problems in noble gas and fluorine chemistry,V:1 The difference in the reactions of the isoelectronic XeOF4 and IF5 with KrF+

The isoelectronic XeOF₄and IF₅ show numerous similarities: molecular geometry, formation of complexes with F^- donors and acceptors, complexation with graphite and with XeF₂. However, on reaction with KrF⁺, IF₅ forms an expected IF₆⁺ ion while XeOF₄ forms XeF₅⁺ and O₂⁺. In this paper we discuss this discordance and present an explanation for it. Nucleophilic displacement on fluorine by IF₅ forms the observed cation while the corresponding reaction with XeOF₄ is predicted to form the hypofluorite (XeF₄-OF)⁺. Subsequent substitution and elimination reactions of this hypofluorite produce the observed product.