Xenon oxyfluorides

In an analogous reaction, xenon oxyfluorides are produced by the reactions... 

Beside XeOs and Xe04, some xenon oxyfluorides are also thermally unstable compounds. They may detonate, particularly at higher temperatures. Other derivatives of the xenon and krypton fluorides involving ligands less electronegative than fluorine should also be assmned to be of low thermodynamic stability. Many derivatives such as perchlorates and trifluoroacetates are known to be explosive. 

Consider the series of xenon oxyfluorides and their relative acidity. Discuss the reasons for the ordering of these compounds. Can you semi-quantify your answer ... 

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

Xenon tnoxide is highly explosive and thus renders any intentional (or unintentional) hydrolysis of these xenon fluorides potentially hazardous. Alternative sources of oxygen to form the oxyfluorides have therefore been proposed 16... 

All possible xenon(IV) and xenon(VI) oxyfluorides are known. Among the xenon(VIII) oxyfluorides, oifly XeOFe is not yet isolated. 

Xe03p2 was the first oxyfluoride of octavalent xenon to be prepared. It was made by reaction of XeFe with sodium perxenate solid at room temperature. Xe03p2 is, like Xe04, sufficiently volatile to distil at 195 K. The much greater volatihty of Xe03p2 as compared to Xe02p2 indicates that the molecule of Xe03p2 is more symmetrical and probably nonpolar (Z>3/,). 

In view of the instability of the trioxide it is interesting to speculate on the stability of the oxyfluorides. Xenon oxide tetrafluoride should be an exothermic compound since the atomic heat of formation using average bond energies of 32 kcal. and 17 kcal. respectively for Xe-F and Xe-O is —160 kcal. mole-. The combined heat of atomization of four fluorine atoms (4 x 18.3 kcal.) and one oxygen atom (59.2 kcals.), 132.4 kcal., is less than this. Xenon dioxide difluoride, by such considerations, should be endothermic. It is of interest that xenon oxide tetrafluoride is easily made by controlled hydrolysis of xenon hexafluoride and is a thermally stable entity (m.p. —28) whereas xenon dioxide difluoride has been observed only mass spectrometrically < >. 

XeFJ fRuFe] (1.36 mmol), prepared as previously described, was mixed with HSO3F (1.41 mmol) in HF (2 ml) with stirring, at 0 , for 5 hr. The [XeF]+[RuFe] appeared to dissolve and a second crystalline phase appeared at the surface of the solution, which assumed a yellow tint. Removal of the HF at 0° yielded a yellow solid, which rapidly turned red-brown and rapidly decomposed with gas evolution, xenon and sulfur oxyfluorides being formed. 

The apparatus and experimental procedures are similar to those used for the tetrafluoride (synthesis 66), except for the use of the heavier-walled vessel H instead of the vessel F. In order to add the required amount of fluorine, it will be necessary either to use a larger vessel G or to repeat the measuring and condensing procedures. The xenon-to-fluorine mol ratios used are about 1 20 [0.689 g. (0.00525 mol) of xenon and 4.18 g. (0.110 mol) of fluorine]. The gas mixture is heated to 300° for 16 hours. The hexafluoride is purified by distillation, the less volatile fraction of lower fluorides being discarded. The purity may be checked by examination of the infrared spectrum, noting the presence of bands at 520 and 612 cm. and the absence of peaks for the difluoride and the tetrafluoride. The spectrum should also be studied in the 900- to 1000-cm. region, where oxyfluorides have fundamentals, for e.xample, XeOF4 at 928 cm. h... 

The structures of fluorides, oxides, and oxyfluorides of xenon discussed in other sections can also be rationalized on the basis of VSEPR theory. Figure 2.22... 

Reaction with KrF2 6, 3.9.4 Reaction with xenon fluorides and oxyfluorides 6, 3.9.3 Reaction with NSF 5, 3.3.4.1 BFe... 

Prior to 1962 the rare gases were frequently called inert gases as no chemical compounds were known (there were a few clathrates and hydrates ), but the realization that the ionization potential of xenon was sufficiently low to be accessible to chemical reaction led to the preparation of several fluorides, oxides, oxyfluorides, and a hexafluoroplatinate of xenon. Several unstable krypton and radon compounds have been synthesized. 

Argon (Ar) gas, for example, is over 30 times more abundant than carbon dioxide and, therefore, not rare. And xenon is not inert it s first compounds were created in 1962. When xenon (Xe) forms binary fluorides and oxides as well as fluoride complexes and oxoanions, the stability of these compounds is very low. It s reactivity is related to increasing atomic size as you go down the table, which leads to a decrease in the first ionization potentials. Xenon tetraflouride (XeF,) is made by mixing one part xenon gas to three parts fluorine gas in a container at 400 °C. Compounds have been confirmed for argon (HArF), krypton (KrF2), xenon (numerous fluorides, oxyfluorides, and oxides), and radon (RnF2). It s believed that compounds exist with helium and neon as well, though none have been experimentally proven to date. 

---