Because of the vast applicability of noble gases, a more detailed understanding of their chemical properties is necessary. Recently, Brock et al. successfully synthesized XeO2 and demonstrated that it has an extended structure in which Xe(IV) is oxygen-bridged to four neighboring oxygen atoms using Raman and O-16/18 isotopic enrichment studies. On the basis of valence shell electron pair repulsion, XeO2 belongs to the AX(4)E(2) arrangement and assumes a local square-planar XeO4 geometry. In contrast, Xe(VIII) assumes a tetrahedral geometry when bound to four oxygen atoms. A theoretical comparison of the four-oxygen-bound Xe(IV) and Xe(VIII) species, based primarily on the density functional theory functional TPSS1KCIS, is presented herein. The properties of XeOn(OH)(4-n)(n-) species, where n is equal to 0, 1, or 2, were evaluated on this basis, and these results are compared with those of the well-known species XeO4.