Oxides of xenon

Oxides. Two oxides of xenon are known xenon trioxide [13776-58-4], XeO, and xenon tetroxide [12340-14-6], XeO (Table 1). Xenon trioxide is most efftcientiy prepared by the hydrolysis of XeE (47) or by the reaction of XeE with HOPOE2 (48). The XeO molecule has a trigonal pyramidal shape Xe—O, 176(3) pm (49), and XeO is tetrahedral with Xe—O, 173.6(2) pm (50). Xenon tetroxide is prepared by the interaction of concentrated sulfuric acid with sodium or barium perxenate, Na XeO, Ba2XeO ( )- Both oxides are thermodynamically unstable, explosive soHds which must be... 

The addition of solid Ba2Xe06 to cold cone H2SO4 produces the second known oxide of xenon, Xe04. This is an explosively unstable gas which may be condensed in a liquid nitrogen trap. The solid tends to detonate when melted but small sublimed crystals have been shown to melt sharply at —35.9°C. Xe04 has only been incompletely studied, but electron diffraction and infrared evidence show the molecule to be tetrahedral. 

Some oxides of xenon are known, and like most other compounds of xenon they are usually obtained from the fluorides. Two reactions that yield Xe03 have already been shown in Eq. (15.237)... 

When all of cationic Ag(II) has been displaced, the oxidation of xenon ceases. Therefore fluoro acid must be supplied to neutralize the XeF2, if oxidation of Xe is to continue ... 

In their early studies of the oxidation of xenon by platinum hexafluoride Bartlett and Jha found [1] that the stoichiometry of the product of that spontaneous reaction varied between XePtF and Xe(PtFg)2. Chemical and physical evidence Indicated that the oxidation state of the platinum in Xe(PtFg)jj was +5. Pyrolysis of XeCPtFg), at 165°, yielded xenon tetra-fluorlde as the only identified volatile product, (xenon itself was not... 

Spontaneous Oxidation of Xenon to Xe(II) by Cationic Ag(II) in Anhydrous Hydrogen Fluoride Solutions... 

Precipitates of AgAsF or AgBF4 sometimes appear when Agp2 is dissolved in the acidified AHF in apparatus that has not been fully dried under high-vacuum conditions. No such Ag(l) salts appear when all is scrupulously dry. Because of the formation of small quantities of Ag(I) salts at the outset, the yields of Xe(ll) based on AgFj are, as a consequence, lower than indicated by eq I and 2. When the product of the AgF2 dissolution in acidified AHF is fluorinaied, to oxidize any Ag(I) formed to Ag(ll) (and to destroy any water remaining in the system) the oxidation of xenon by the cationic Ag(II) is in accord with the requirement 2Ag(II) -F Xe(0) 2Ag(l) + Xe(II) (3)... 

The spontaneous oxidation of xenon by fluorine in the presence of a Lewis acid fluoride. A, was observed to occur only in the liquid phase. There was no interaction between Xe, F2 and ASF5 (strongest A) in the gas phase, in the dark, at 20°C at a total pressure of 10 atmospheres, over one day. When this mixture was cooled to -60°C... 

Catalysis by [MnF6]2- derivatives of the thermal reaction between Xe and F2 at 120 °C has been investigated 14 the reaction is first-order in the Xe concentration and zeroth-order with respect to F2. The oxidation of xenon to [XeF]+ by [BrF6]+, which is itself generated by Kr11 cations,11 demonstrates the relative fluorinating ability of these two noble gases in the +2 state. 

The enthalpies of formation of the xenon fluorides are negative (Table 22.1), which suggests that these compounds should be reasonably stable. This is indeed found to be the case. They are, however, powerful fluorinating agents and must be handled in containers that do not readily react to form fluorides. The enthalpies of formation of the oxyfluorides and oxides of xenon, on the other hand, are positive, so these compounds are quite unstable. 

The principal neutral, cationic, and anionic fluorides oxide fluorides and oxides of xenon are listed in Table I along with their geometries. 

No complex salts or molecular adducts derived from the known oxofluorides and oxide of xenon in the -1-8 oxidation state, namely, Xe03F2, Xe02F4, and Xe04, are known. 

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