Xenon hexafluoride

One interesting suggestion [3] was that XeFg has a low-lying electronic triplet state, significantly populated at room temperature, which would be deformed by the Jahn-Teller effect. In the resulting 03 molecular symmetry, the Ti electronic state of Ob would separate into A2u and E states. This idea was supported by studies [4] of vibrational spectra, both of the gas phase and of samples isolated in a matrix of sohd argon. Octahedral XeFs would have only two IR-active modes (one stretch and one deformation) and 

Radial distribution curve for electron diffraction by gaseous XeFg. The continuous line represents the experimental curve, and the dashed line is theoretical curve calculated for a model with Oh symmetry. Redrawn with permission from [1], Copyright 1968, American Institute of Physics. 

Although a xenon hexafluoride molecule with symmetry would have two chemically distinct types of fluorine atom, the rapid pseudorotation would make them equivalent in the NMR spectrum of a solution at 

Views of the polymeric xenon hexafluoride aggregates found in the cubic phase. Redrawn with permission from [11]. Copyright 1974 American Chemical Society. Xenon atoms are represented by small circles and bridging fluorine atoms by large circles. In (a) the tetramer is viewed with the 4 axis parallel to [001 ], and in (b) the hexamer is shown with a 3-fold axis parallel to [111]. 

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The higher fluorides are prepared using excess fluorine (Figure A). All these compounds are stable in dry air at room temperature. However, they react with water te form compounds in which one or more of the fluorine atoms has been replaced by oxygen. Thus xenon hexafluoride reacts rapidly with water to give the trioxide... 

The starting point for the synthesis of xenon compounds is the preparation of xenon difluoride, XeF2, and xenon tetrafluoride, XeF4, by heating a mixture of the elements to 400°C at 6 atm. At higher pressures, fluorination proceeds as far as xenon hexafluoride, XeFfi. All three fluorides are crystalline solids (Fig. 15.27). In the gas phase, all are molecular compounds. Solid xenon hexafluoride, however, is ionic, with a complex structure consisting of XeF< + cations bridged by F anions. 

See Xenon hexafluoride Caesium nitrate Xenon tetrafluoride... 

See Xenon hexafluoride Water (reference 2) Xenon tetrafluoride oxide Caesium nitrate... 

Although uncontrolled reaction of xenon hexafluoride and moisture produces explosive xenon trioxide, controlled action by progressive addition of limited amounts of water vapour with agitation to a frozen solution of the hexafluoride in anhydrous hydrogen fluoride at —196° C to give xenon oxide tetrafluoride or xenon dioxide difluoride is safe [1], Controlled hydrolysis in solution in hydrogen fluoride is, however, described as hazardous [2],... 

Nitryl fluoride Non-metals Oxygen (Gas) Hydrogen Palladium(II) oxide Hydrogen Xenon hexafluoride Hydrogen... 

It is a powerful explosive [1] produced when xenon tetrafluoride or xenon hexafluoride are exposed to moist air and hydrolysed. Some tetrafluoride is usually present in xenon difluoride, so the latter is potentially dangerous. Although safe to handle in small amounts in aqueous solution, great care must be taken to avoid solutions drying out, e.g. around ground stoppers [2], Full safety precautions have been discussed [2,3,4], Precautions necessary for use of aqueous solutions of the trioxide as an epoxidation reagent are detailed [5,6], A safe method of preparation,... 

Xenon hexafluoride is known to exist in condensed phases as an equilibrium mixture that can be shown as... 

Xenon fluorides, 77 323-325 binary, 77 335-336 Xenon-gold cations, 77 332 Xenon halides, 77 323-325 Xenon hexafluoride, 7 7 325, 329 uses for, 7 7 336 Xenon ion lasers, 74 685 Xenon isotopes, in fission reactors, 77 375 Xenon oxide difiuoride, 77 326 Xenon oxide fluorides, 7 7 326 Xenon oxides, 77 325-326 Xenon oxide tetrafluoride, 77 326 Xenon testing, in plastics weathering, 79 584-585... 

Fig. 5. Stepwise dissociation energies for the xenon hexafluoride cation. 

Xenon dilluoride, 4332 Xenon dilluoride oxide, 4319 Xenon hexafluoride, 4377 Xenon tetralluoride, 4353... 

Tetrafluoroammonium hexafluoromanganate, 4384 Tetrafluoroammonium hexafluoronickelate, 4385 Tetrafluoroammonium hexafluoroxenate Tetranitromethane, 0546 Titanium tetraperchlorate, 4170 1,1,1 -Triacetoxy-1,2-benziodoxol-3-one, 3610 Trifluoromethyl hypofluorite, 0353 Trimethylsilyl chlorochromate, 1301 Trioxygen difluoride , 4323 Uranium hexafluoride, 4375 Vanadium(V) oxide, 4866 Vanadium trinitrate oxide, 4763 Vanadyl perchlorate, 4152 Xenon hexafluoride, 4377 Xenon(II) pentafluoroorthoselenate, 4382 Xenon(II) pentafluoroorthotellurate, 4383 Xenon tetrafluoride, 4353 Xenon tetrafluoride oxide, 4346 Xenon tetraoxide, 4863 Xenon trioxide, 4857 Zinc permanganate, 4710... 

In the 1960s, scientists first produced compounds of xenon and some other noble gases at the Argonne National Laboratory located near Chicago. Xenon and krypton are the only noble gases that readily form compounds with oxygen and fluorine. For instance, when xenon combines with fluorine, it can form a series of compounds, such as xenon difluoride PCeF ), xenon tetra-fluoride (XeF ), and xenon hexafluoride pCeF ). These and other compounds of xenon are formed within metal containers at high temperatures and pressures. They are not stable. 

The oxyfluoride, XeOF4 is a stable colorless liquid produced by the reaction of xenon hexafluoride with sodium nitrate ... 

Other nucleophilic fluorination processes in heterocycles have included displacement of bromine with potassium, cesium, or silver fluorides, but these failed to work for 4-bromo-5-nitroimidazole and ethyl 4-bromoimid-azole-5-carboxylate (73JA4619). Xenon hexafluoride was reported to convert 2,4,5-tribromoimidazole into the trifluoro analogue (79JGU1251). 

Compounds with six fluorine ligands have provided structural difficulties. Xenon hexafluoride exists as the monomer in the vapour state and has been shown largely by electron diffraction experiments to be non-octahedral, and also fluxional.44 Although VSEPR theory might have... 

Xenon difluoride and xenon hexafluoride fluorinate pyridine to give a mixture of 2- and 3-fluoropyridines along with 2,6-difluoropyridine (76JFC(7)179). Cesium fluoroxysulfate at room... 

Fig. 6.13 Possible molecuLir structures of xenon hexafluoride (a) lone pair emerging through face of the octahedron. Ci, symmeiry (b) lone pair emerging through edge of octahedron,...

There are actually four phases known of solid xenon hexafluoride. All have several structural features in common, and the phase described here, phase IV or the cubic phase, is the easiest lo describe. 

Careful hydrolysis of xenon hexafluoride produces xenon teuafluoride oxide ... 

Complete hydrolysis of xenon hexafluoride or hydrolysis or disproportionation of xenon tetmfluoride produces the tnoxide ... 

Xenon hexafluoride can act as a Lewis acid. It reacts with the heavier alkali fluorides to form seven-coordinate anions, which in turn can rearrange to form eight-coordinate species ... 

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