Xenon oxide, XeO

Xenon tetrafluoride forms stable colorless crystals. Two other xenon fluorides, Xep2 and XeFg, were synthesized by the group at Argonne, and a highly explosive xenon oxide (XeOs) was also found. The xenon fluorides react with water to form hydrogen fluoride and oxycompounds. For example ... 

Since the discovery of the first noble gas compound, Xe PtF (Bartlett, 1962), a number of compounds of krypton, xenon, and radon have been prepared. Xenon has been shown to have a very rich chemistry, encompassing simple fluorides, XeF2> XeF, and XeF oxides, XeO and XeO oxyf luorides, XeOF2> XeOF, and Xe02 2 perxenates perchlorates fluorosulfates and many adducts with Lewis acids and bases (Bartlett and Sladky, 1973). Krypton compounds are less stable than xenon compounds, hence only about a dozen have been prepared KrF and derivatives of KrF2> such as KrF+SbF, KrF+VF, and KrF+Ta2F11. The chemistry of radon has been studied by radioactive tracer methods, since there are no stable isotopes of this element, and it has been deduced that radon also forms a difluoride and several complex salts. In this paper, some of the methods of preparation and properties of radon compounds are described. For further information concerning the chemistry, the reader is referred to a recent review (Stein, 1983). 

This behavior provides evidence that in each of the compounds, radon is in the +2 oxidation state When higher-valent xenon compounds, such as XeF and XeF, are hydrolyzed, water-soluble xenon species (XeO and XeO ) are produced (Malm and Appelman, 1969). We have observed no radon species corresponding to these xenon species in hydrolysis experiments. 

Xenon tetraoxide (XeO ) exhibits xenon with a +8 oxidation state. It is a very unstable and explosive gas. The ion of xenon has also been compounded with platinum to form XePtFg. 

Compounds in oxidation states +2, +4, +6, and +8 are well known. The tetrafluoride and hexafluoride are readily hydrolyzed by water forming xenon trioxide, XeOs, and the xenon tetraoxide, Xe04, both of which are dangerously explosive. While the trioxide XeOs is a colorless crystalline solid, stable in solution, the tetraoxide Xe04 is a colorless unstable gas. 

Among xenon oxides only XeOs and Xe04 have been definitively isolated and characterized. XeO is known, as a gas-phase species, to be bound with respect to a D(0) atom but not with respect to ground-state P(0). There is no evidence for a condensed phase XeO species. Recently, however, the unique radical, HXeO, has been isolated by UV photolysis of either H20/Xe or N20/HBr/Xe solid mixtures as 7K. The compound was characterized by IR and its intrinsic stability supported by ab initio calculations. ... 

Xenon trioxide, XeOs, is reduced to xenon in acidic solution by iodide ion. Iodide ion is oxidized to iodine, I2. Write a balanced chemical equation for the reaction. 

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... 

Russian scientists (Avrorin et al., 1981, 1985) have reported that reactions of complex mixtures of radon, xenon, metal fluorides, bromine pentafluoride, and fluorine yield a higher fluoride of radon which hydrolyzes to form RnO. However, efforts to confirm these findings have been unsuccessful. In similar experiments which have been carried out at Argonne National Laboratory (Stein, 1984), it has been found that radon in the hydrolysate is merely trapped in undissolved solids centrifugation removes the radon from the liquid phase completely. This is in marked contrast to the behavior of a solution of XeO, which can be filtered or centrifuged without loss of the xenon compound. Hence there is no reliable evidence at present for the existence of a higher oxidation state of radon or for radon compounds or ions in aqueous solutions. Earlier reports of the preparation of oxidized radon species in aqueous solutions (Haseltine and Moser, 1967 Haseltine, 1967) have also been shown to be erroneous (Flohr and Appelman, 1968 Gusev and Kirin, 1971). 

Xenate solutions may also be oxidized directly to perxenate with ozone. Solid per.xe-nates are rather insoluble and are unusually stable for xenon-oxygen compounds Most do not decompose until healed above 200 °C. X-ray crystallographic structures have been determined for several perxenates, and they have been found to contain the octahedral XeO " ion, which persists in aqueous solution (possibly with prolonation to HXeO "),... 

Xenon tetrafluoride and hexafluoride are very powerful oxidizing agents also. They are particularly dangerous because they react with water, giving explosive xenon trioxide. [See Cautions under the syntheses of XeF and XeO solution. The best way to dispose of xenon tetrafluoride or hexafluoride is to rinse the vessel [e.g., a protective trap) first with carbon tetrachloride and then with plenty of water, otherwise explosions may occur.)... 

Three stable oxyfluorides have been characterized XeOF4 and Xe02F2 with Xe in the -1-6 oxidation state, and Xe03F2 with Xe in the - -8 oxidation state. These are obtained by controlled hydrolysis of xenon fluorides or by fluorination of xenon trioxide. The oxyfluoro anions, [XeOgF] and [(XeOF4)3F] result when the hydrolysis products of XeOs and XeOF4 are treated with F. ... 

Previous suggestions on the mechanism of hydrolysis of xenon difluoride have been confirmed/ The first intermediate is XeO, which interacts with water to give hydrogen peroxide. Oxidation of hydrogen peroxide by Xep2 has already been investigated, and involves a chain reaction initiated by reaction between XeO and H2O2. 

Xenon species. The NpOi ion and other oxidation states react with XeOs and OH to form Np see 3.6.1 Peroxide for some products. 

Xenon species. Aqueous XeOs oxidizes Mn to Mn02-aq and Mn04". 

---