The XeF2–MF5(M = Sb, Ta, or Nb) systems: vibrational spectra of solid xenon difluoride adducts

Abstract

The i.r. and Raman spectra of the compounds 2XeF₂·MF₅(M = Sb or Ta). XeF₂·MF₅, and XeF₂·2MF₅(M = Sb, Ta, or Nb) have been measured, and it has been shown that, although the spectra are best interpreted in terms of ionic formulations involving [XeF]⁺ and [Xe₂F₃]⁺, there is increasing covalent character in the series, XeF₂·SbF₅ < XeF₂·TaF₅ < XeF₂·NbF₅, XeF₂·2SbF₅ < XeF₂·2TaF₅ < XeF₂·2NbF₅ and 2XeF₂·SbF₅ < 2XeF₂·TaF₅.

Weight-loss versus time-of-pumping studies on the products of reaction of large excesses of XeF₂ with the pentafluorides have shown that, in addition to the simple 2:1, 1 : 1, and 1 : 2 compounds, species with compositions [2XeF₂·Xe₂F₃]⁺[SbF₆]^–, [XeF₂·XeF]⁺[TaF₆]^–, and [XeF₂·XeF]⁺[NbF₆]^– are also formed.