Vibrational Spectra and Structure of XeO2F2

The Raman spectra of liquid and solid XeO₂F₂ and the infrared spectrum of XeO₂F₂ in an argon matrix at liquid-helium temperature are reported. They are interpreted in terms of C_2υ molecular symmetry which can be associated with a molecule of pseudobipyramidal structure, where the two F atoms are axial to the Xe and the two O atoms with a lone electron pair are equatorial. The vibrational spectra support the existence of primarily monomeric XeO₂F₂ molecules in the liquid state and quite probably in the solid. The nine fundamentals assigned are: 848 (ν₁), 490 (ν2), 333 (ν3), 198 (ν4), 224 (ν5), 905 (ν6), 324 (ν7), 585 (ν8), and 317_(ν9).