By taking advantage of the Lewis acid properties of the XeF+ and KrF+ cations, it has been possible to prepare a diverse range of noble-gas adduct cations; FXeL+, FKrNCH+ and FKrNCRF+ (L HCN, RCN, RFCN, C5F5N, sC3F3N3). The adduct salts have stabilities which range from explosive at −60 °C for FKrNCH+AsF6− (the first example of a KrN bond), to stable at room temperature for sC3F3N2NXeF+AsF6− and have been characterized by multi-NMR spectroscopy and Raman spectroscopy. We have recently extended this work to the related noble-gas cations XeOTeF5+ and XeOSeF5+, to yield the first examples of OXeN linkages, and to the inorganic base F3SN. The adduct cation FXeNSF3+ undergoes successive additions of HF to the NS bond in anhydrous HF to give the adduct cations FXeN(H)SF4+ and FXeN(H2)SF5+. The FXeN(H2)TeF5+ cation has also been synthesized.The study of fluoro-anions having coordination numbers higher than six and, in particular, those involving at the same time free valence electron pairs, have recently received considerable interest. To a large extent, these studies have been greatly facilitated by the realization that anhydrous N(CH3)4+F− is an excellent reagent for the preparation of novel, high-oxidation state complex fluoride or oxofluoride anions. We have recently synthesized (CH3)4N+XeF5− by the reaction of stoichiometric amounts of XeF4 and N(CH3)4+F− in dry CH3CN. The salt was fully characterized by Raman spectroscopy, 19F and 129Xe NMR spectroscopy and X-ray crystallography. The XeF5− anion has a pentagonal planar (D5h) structure with five equivalent fluorines and is of considreable significance as it represents the first example of an AX5E2 (E = valence electron lone pair) system.The syntheses and structural characterization of other high-coordination number hypervalent fluoro- and oxofluoro- anions of xenon will also be discussed, i.e., XeF5O−, XeF7−, XeOF3−, XeO2F3−.