Gas noble

The noble gases, also known as rare or inert gases, form Gronp 18 of the Periodic Table, embedded between the alkah metals and the halogens. The elements hehum, neon, argon, krypton, xenon, and radon are the members of this group. 

The chemical inertness of the noble gases is based on their electronic structure. Each element has a completely filled valence shell. In fact their inertness helped to develop the key idea of a stable octet 

Until 1962 only physical inclusion compounds were known. Argon, krypton, and xenon form cage or clathrate compounds with water (clathrate hydrates) and with some organics such as quinol. The host molecules are arranged in such a way that they form cavities that can physically trap the noble gas atoms, referred to as guests. The noble gas will be released upon dissolution or melting of the host lattice. 

Reviews about the chemistry of noble gases including the cations of xenon and krypton 

A large number of Xe + cations (n 30) have been detected by mass spectrometry,1048 and the Xe2+ ion was first generated in the solution phase in 1978.1049 Drews and Seppelt1050 were the first, however, to report the isolation and molecular structure of Xe2+Sb4F21- (365) [Eq. (4.255)]. In the crystals of the dark green compound, weak multiple contacts exist between xenon and fluorine atoms. The Xe—Xe bond is surprisingly long (3.087 A) but much shorter than the theoretically predicted values (3.17-3.27 A). 

In solution chemistry too attempts have been made to protonate xenon to XeH+ in the superacid media.150 1038 Evidence for the protonation comes from suppression of proton-deuterium exchange rates of deuterium gas in the presence of xenon in strong acid medium.342 

In 1989 the synthesis and isolation of the first compounds with stable Xe—C bond were reported by Naumann and Tyrra285 and Frohn and Jakobs1068 by the introduction of the organic group through nucleophilic substitution called xenodeborylation [Eq. (4.256)]. The boron as Lewis acid center polarizes the Xe—F bond and thereby allows it to overcome the low electrophilicity of the Xe center to form the fluoroar-ylxenonium fluoroborates 366. When the reaction is carried out in anhydrous HF, all C6F5 groups of the borane are transferred to xenon [Eq. (4.256)].1069 

Frohn and coworkers have obtained the unique chloronium cation 374,1120 which is the first unambiguously characterized xenon(II) chlorine compound [Eq. (4.261)]. There is no strong contact between cation 374 and the anion in the solid state. The two C—Xe—Cl contacts are linear (bond angles = 176.0 and 178.8°) with shorter C—Xe (2.111 and 2.116 A) and longer Xe—Cl (2.784 and 2.847 A) bond lengths. The Xe—Cl—Xe bond angle is 116.96°. 

McDowell performed ab initio calculations at the B3LYP and MP4(SDQ) level on H-Ar-Cl. The NBO analysis places a larger positive charge on the Ar atom while the AIM value is about the same (0.32) for both Ar and H. The calculated positive Laplacian of the electron density at the Ar-Cl BCP indicates that the Ar-Cl bond is dominated by electrostatic attraction, whereas the negative value for the Ar-H bond indicates a covalent interaction. 

Another method was to start with air and remove from it oxygen, carbon dioxide, and water vapor. Invariably, the nitrogen from air was a little denser (by about 0.5 percent) than the nitrogen from ammonia. 

Lord Rayleigh s work caught the attention of Sir William Ramsay, a professor of chemistry at the University College, London. In 1898 Ramsay passed nitrogen, which he had obtained from air by Rayleigh s procedure, over red-hot magnesium to convert it to magnesium nitride  

After all of the nitrogen had reacted with magnesium, Ramsay was left with an unknown gas that would not combine with 

With the help of Sir William Crookes, the inventor of the discharge tube, Ramsay and Lord Rayleigh found that the emission spectrum of the gas did not match any of the known elements. The gas was a new element They determined its atomic mass to be 39.95 u and called it argon, which means the lazy one in Greek. 

The discovery of the noble gases helped to complete the periodic table. Their atomic masses suggested that these elements should be placed to the right of the halogens. The apparent discrepancy with the position of argon was resolved by Moseley, as discussed in Section 2.3. 

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Inert gases A semi-obsolete name for the noble gases. ... 

Used (particularly He, Ar) to provide an inert atmosphere, e.g. for welding, and in electric light bulbs, valves and discharge tubes (particularly Ne). Liquid He is used in cryoscopy. The amounts of He and Ar formed in minerals by radioactive decay can be used to determine the age of the specimen. Xe and to a lesser extent Kr and Rn have a chemistry the other noble gases do not form chemical compounds. 

Except for the n = 1 quantum level the maximum number of electrons in the outermost quantum level ofany period isalwayseight. At this point the element concerned is one of the noble gases (Chapter 12). 

When Mendeleef devised his periodic table the noble gases were unknown. Strictly, their properties indicate that they form a group beyond the halogens. Mendeleef had already used Group VIIl to describe his transitional triads and the noble gases were therefore placed in a new Group O. 

Since 1916 it has been discovered that some noble gases (originally called the inert gases) do form compounds and also there are many reactions known in which elements do not achieve a noble gas configuration. Nevertheless, the theory was a considerable advance towards modem ideas and provides a good basis for discussion. 

Industrially, elemental nitrogen is extracted from the air by the fractional distillation of liquid air from which carbon dioxide and water have been removed. The major fractions are nitrogen, b.p. 77 K and oxygen, b.p. 90 K, together with smaller quantities of the noble gases. 

It is one of the "noble" gases. It is characterized by its brilliant green and orange spectral lines. 

MAIN GROUP INORGANICS, NOBLE GASES, AND ALKAEI METALS... 

The noble gases are mostly unreactive. In some instances, they act mostly as a place holder to fill a cavity. For dynamical studies of the bulk gas phase or liquid-phase noble gases, hard-sphere or soft-sphere models work rather well. 

Paradoxically, compounds incorporating bonds with noble gases are difficult to model. This is because a very accurate method is needed in order to correctly... 

Closed shell electron configuration (Sections 1 1 and 116) Stable electron configuration in which all the lowest energy orbitals of an atom (in the case of the noble gases) an ion (e g Na" ) or a molecule (e g benzene) are filled... 

Noble gases (Section 1 1) The elements in group VIIIA of the penodic table (helium neon argon krypton xenon radon)... 

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