Krypton, discovery

Following Bartlett s discovery of xenon hexafluoroplatinate(VI), xenon and fluorine were found to combine to give several volatile, essentially covalent fluorides, and at least one fluoride of krypton has been obtained. From the xenon fluorides, compounds containing xenon-oxygen bonds have been made much of the known chemistry of xenon is set out in Figure 12.1. 

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). 

Sir William Ramsay, 1852-1916. Scottish chemist and physicist. Discoverer of the inert gases. Lord Rayleigh was a co-discoverer of argon, and M. W. Travis collaborated in the discovery of krypton, neon, and xenon. After F. E. Dorn had discovered radon, or radium emanation, Ramsay and Whidaw Gray determined its density and proved it to be the heaviest member of the argon family. 

From this clue came also the later discovery of three other inert elements of the air. From liquid argon, the same scientists separated new neon, hidden krypton, and xenon (the stranger) present to the extent of one part in eighty thousand, twenty million, and one hundred and seventy million parts of air respectively. With modern apparatus at his disposal it is not difficult to believe that Cavendish might have been the discoverer of these noble gases one hundred years before they were given to the world. 

After helium and argon had been discovered the existence of neon, krypton, xenon, and radon was clearly indicated by the periodic law, and the search for these elements in air led to the discovery of the first three of them radon was then discovered during the investigation of the properties of radium and other radioactive substances. While studying the relation between atomic structure and the periodic law Niels Bohr pointed out that element 72 would be expected to be similar in its properties to zirconium. G. von Hevesy and D. Coster were led by this observation to examine ores of zirconium and to discover the missing element which they named hafnium. 

Prior to 1982, the measurement of more than one andgen amultaneously by flow cytometry required two lasers—an argon-ion laser to excite fluorescein (at 488 nm) and a krypton or a dye laser to excite rhodamine or one of its deriva-dves. The discovery of a naturally occurring fluorochrome, phycoerythrin (PE), changed this (i). PE is a phycobiloprotein found in red adgae. It can be excited efficiently at 488 nm (simultaneously with fluorescein) and has a peak fluorescence at 578 nm, sufficiently removed from the peak of 520 nm from fluorescein. There is some overlap in the emission spectra from the two dyes (in pardcular, there is sdll some emission from fluorescein above 580 nm) and this must be corrected, either electronically or by the computer software. 

Within a year of the discovery of XePtFe and as a result of worldwide activity, it was clear that the chemistry of the noble gases would be limited to the heavier elements as set out in my Noranda Lecture (see Ref. S2). Because of the dangerous radioactivity associated with all of the radon isotopes, this meant that the bulk of noble-gas chemistry would be that of xenon. The chemistry of krypton appeared to be limited to KrF2 and compounds that could be derived from it. In all cases, it was clear, the range of accessible noble-gas chemistry was dictated by lower ionization potentials at the noble-gas atom, and high electronegativity and small size of the ligand atoms, as discussed in Ref. 45. 

Amazingly, they found it. The discovery of these three gases was a great credit to their skills as researchers. They suggested the name krypton for the new element. The name was taken from the Greek word kryptos for hidden. ... 

The proper location of radon in the periodic table was determined by Scottish chemist Sir William Ramsay (1852-1916). Ramsay was also involved in the discovery of three other noble gases neon, krypton, and xenon. In 1903, Ramsay was able to determine the atomic weight of radon. He showed that it belonged beneath xenon in Group 18 (VIIIA) of the periodic table. 

Diatomic noble gas ions and diatomic hydride ions involving argon have been observed since the i930 s 11 and [ArN]+ 50) and [Arl]+ S1) were observed in collision experiments in mass spectrometers in 1960. However, none of these species were isolable as stable solids. Following the discovery of stable krypton and xenon fluorides and, in particular, recognition of the enhanced stability of [KrF]+ and [XeF]+ in crystalline solids, there has been renewed interest in the possibility of obtaining other related species. 

By 1898, Ramsay and his assistant Morris Travers (1872-1961) had discovered neon, krypton, and xenon. All of them were chemically inert, so they were called the noble gases (they would not mix with common elements), and also they could be found in trace amounts in atmospheric air. In terms of the periodic table, this meant that a new column was needed, but, rather than disrupt the whole system, it actually confirmed the utility of the periodic system. Ramsay had predicted the characteristics of the new elements, and their characteristics had come out close to the expected values in each case. The last element of the column was added in 1903 with the discovery of the radioactive element radon by Frederick Soddy. In 1904, Ramsay won the Nobel Prize for chemistry for his work. 

In 1962 the first chemical noble gas compound, formulated as XePtFg, was synthesized by Neil Bartlett. This result spurred intense research activity and led to the discovery of numerous xenon and krypton compounds. In 2000 the formation of the first argon compound, argon fluorohydride (HArF), was reported by Leonid Khriachtchev and colleagues, see also Argon Cavendish, Henry Helium Krypton Neon Ramsay, William Ruthereord, Ernest Soddy, Frederick Strutt, John Xenon. 

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