Bonding and Electronic Structure of XeF₃^-

Abstract

The xenon-fluoride bond dissociation energy in XeF3- has been measured by using energy-resolved collision-induced dissociation studies of the ion. The measured value, 0.84 +/- 0.06 eV, is higher than that predicted by electrostatic and three-center, four-electron bonding models. The bonding in XeF3- is qualitatively described by using molecular orbital approaches, using either a diradical approach or orbital interaction models. Two low-energy singlet structures are identified for XeF3-, consisting of Y- and T-shaped geometries, and there is a higher energy D3h triplet state. Electronic structure calculations predict the Y geometry to be the lowest energy structure, which can rearrange by pseudorotation through the T geometry. Orbital correlation diagrams indicate that that ion dissociates by first rearranging to the T structure before losing fluoride.

NMR Spectroscopic Evidence for the Intermediacy of XeF3− in XeF2/F− Exchange, Attempted Syntheses and Thermochemistry of XeF3− Salts, and Theoretical Studies of the XeF3− Anion

“…Finally, a Y-shaped anion (D3h) was also computed as a diradical species, in accord with the structure predicted by MO theory, 14 Calculations performed in the present work (DFT using the PBE1 functional, and CCSD; basis sets: aVTZ (for F) and aVTZ(-PP) (for Xe) were done without symmetry constraints, and reveal that the global-energy minimum of the anion is the F2Xe---F -adduct (Cs symmetry), in Figure 3a). For the DFT structure, one of the Xe-F bonds is distinctly longer (2.378 Å) than the other two (2.045 and 2.099 Å), but well within the sum of the van der Waals radii for Xe and F.…”

“…The structure computed at the CCSD/aVTZ level of theory was found to possess similar geometric parameters to that of the DFT structure (Table 1). It is unclear why the XeF3 -anion was computed to be an energy minimum in the previous study 14 since the structure remains a transition state even when the calculations are performed using the same basis set-density functional combination as employed in the original work.…”

Atypical Compounds of Gases, which Have Been Called “Noble”

“…and contain Xe at oxidation states +2, +4, +6, +8 (Fig. 1), or Kr II in fluoride environment; chemistry of 'classical' Ng compoundsalso undergoing violent progress 9 -has been reviewed elsewhere [10][11][12] and only rarely will be mentioned here. 13 Whatever goes beyond that (and any chemical bonding involving Ar) will be treated as 'atypical', and described from a chemical perspective to a greater detail, with particular emphasis on chemistry of Xe.…”

Molecular CsF5 and CsF2+

“…As econd structure derives from a D 3h star-shaped molecule.S uch as pecies would share the electronic characteristics of the isoelectronic (and known [20,21] )X eF 3 À ion in being ac lassic Jahn-Teller system. Tw oelectrons would occupy an e orbital, with deformations to Tand Ys hapes expected.…”