Noble gases krypton difluoride

Although a noble gas, krypton is not entirely unreactive. One krypton compmmd, krypton difluoride (KrF2), is commercially available in small quantities. SEE ALSO Gases Noble Gases Ramsay, William Travers, Morris. 

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). 

The difference in the ionization potentials of xenon and krypton (1170 versus 1351 kj/mol) indicates that krypton should be the less the reactive of the two. Some indication of the difference can be seen from the bond energies, which are 133 kj/mol for the Xe-F bond but only 50 kj/mol for the Kr-F bond. As a result, XeF2 is considerably more stable of the difluorides, and KrF2 is much more reactive. Krypton difluoride has been prepared from the elements, but only at low temperature using electric discharge. When irradiated with ultraviolet light, a mixture of liquid krypton and fluorine reacts to produce KF2. As expected, radon difluoride can be obtained, but because all isotopes of radon undergo rapid decay, there is not much interest in the compound. In this survey of noble gas chemistry, the... 

Krypton is a rather dense, tasteless, colorless, odorless gas. Its critical temperature is between that of oxygen and carbon dioxide. It is extracted during fractional distillation of liquid oxygen at a temperature of about -63.8°C. At one time it was thought that krypton, as well as the other noble gases, were completely inert. However, in 1967 scientists were able to combine fluorine with krypton at low temperatures to form the compound krypton difluoride (KrFj). In this case krypton has a valence of 2. 

They were called the inert gases, because it was thought j that they would not react with other elements. Helium and I Neon are not known to com-I bine with other elements. How-j ever, compounds of the higher members of the noble gas I group have been found, this is i due to the presence of d orbit- als (e.g. xenon tetrafluoride and I krypton difluoride). 

Despite xenon s relatively high reactivity (which isn t really high at all) the Group 18 elements 2ire considered unreactive monatomic gases. The only other noble gas to form any compound is krypton, which can form a very unstable difluoride binary compound. Compounds of noble gases, typically that of xenon, have oxidation states of +2, +4, +6, and +8. 

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