Xenon trioxide difluoride: Mass spectrum

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XENON TRIOXIDE DIFLUORIDE : MASS SPECTRUM J . L . Huston Department of Chemistry, Loyola University, Chicago, Illinois (Received 6 November 1967)

XENON TRIOXIDE difluoride, a new compound and the first oxyfluoride of octavalent xenon, was generated by reaction at room temperature of xenon hexafluoride with sodium perxenate solid . It was formed along with a larger quantity of other xenon compounds (principally XeOF 4) inside a Kel-F system and was identified by distilling the mixture back and forth past a Kel-F valve leading to the source of a time-of-flight mass spectrometer . Mass spectra were displayed on the screen of an oscilloscope and the patterns, changing as distillation proceeded, were photographed . The spectrum of the new compound is shown in Fig . 1 .

FIG . 1 . Mass spectrum of Xe03F2 . Electron energy 70 e .v ., pulsed electron beam . The two faint peaks at masses 193 and 195 (between XeOF2 + and Xe03F+) are due to Xe04 which was formed along with Xe03F2 and could not be removed . 2,



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XENON TRIOXIDE DIPLUORIDE

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Portions of the spectrum were identified by reference to the spectra of known xenon compounds . In particular, XeO 2F 2+ was identified by reference to the XeOF 3+ pattern of XeOF 4 and verified by reference to the parent molecule-ion of Xe0 2 F2 .

XeO 3F2 + ,

the parent molecule-ion of the new compound, was identified by reference to the overlapping xenon isotopic pattern of the parent molecule-ion of XeOF4 . Xenon tetroxide, hitherto the most volatile xenon compound (1), was formed in small quantity along with XeO 3F2 .

Careful

study of pictures taken as rapidly as possible as the two distilled past the mass spectrometer inlet failed to show any substantial difference in their volatilities . Like Xe0 4 (2), XeO3F2 is sufficiently volatile to distill at dry ice temperature . The much greater volatility of Xe0 3F2 as compared to Xe0 2F2 indicates the molecule of the former is the more symmetrical and probably non-polar . Previous attempts to form a new volatile compound of Xe(VIII) by fluorination of Xe0 3 or Xe04 with CIF3 or XeF6 had failed to produce evidence for a new compound . When an attempt was made to fluorinate Xe0 4 with KrF2 (3) no reaction was observed and the two compounds simultaneously entered the mass spectrometer from a room temperature mixture . Perhaps the generation of XeO 3 F2 from Na4 XeO 6 can be compared to the generation of a volatile acid or acid anhydride by the action of a less volatile acid on an appropriate salt . References 1 . H . SELIG, H . H . CLAASSEN, C . L . CHERNICK, J . G . MAIM and J . L . HUSTON, Science 143, 1322 (1964) . 2 . J . L . HUSTON, M . H . STUDIER and E . N . SLOTH, Science 143, 1161 (1964) . 3 . The sample of KrF was kindly furnished by John Malm and Felix Schreiner oI Argonne National Laboratory .