Xenon, liquid

Paige M E, Russell D J and Harris C B 1986 Studies of chemical reactivity in the condensed phase. II. Vibrational relaxation of iodine in liquid xenon following geminate recombination J. Chem. Phys. 85 3699-700... 

Batista V S and Coker D F 1996 Nonadiabatic molecular dynamics simulation of photodissociation and geminate recombination of liquid xenon J. Chem. Phys. 105 4033-54... 

Liquid xenon, used as a solvent, will burst sealed apparatus if allowed to warm up. Pressure relief valves are recommended. 

We have recently prepared some new and very thermolabile CO- and N2 comPlexes derived from titanocene [1] or decamethyltitanocene [2], and have characterized them by their vibrational spectra. As well as "classical" matrix spectroscopy, we have used spectroscopy in liquid xenon (LXe). The application of chemistry and methodology indicates the decamethylsilicocene structure, which represents the first example of a stable jt-complex of divalent silicon [3]. Reaction with CO or N2 leads to the two title complexes [4] ... 

We have used such cells (J 4) to generate and measure the kinetic stability over a wide temperature range of a wide variety of unstable species. The easiest experiments - and the first performed - were simply the photolysis of a metal carbonyl in liquid xenon doped with dissolved N2 and hence replacement of CO by N2. The V(N-N) IR bands are little weaker than v(C-O) bands and hence detection and characterization are straightforward, particularly when use is made of previous matrix studies. Species examined include Cr (CO) (N )x x = Ni(CO)3(N ) ( 16). ... 

The liquid xenon technique was also used for preparing the analogous nitrogen complex /17/. 

The more nitrogen the complexes contain, the less stable they are. The last member of the series, chromium hexanitrogen, was not detected, probably because it is too unstable at the temperature of liquid xenon. Other complexes and reactions were also studied, using liquid xenon or liquid krypton as the solvent. A list is given in Table 1. 

The most important application of organolithium reagents is their nucleophilic addition to carbonyl compounds. One of the simplest cases would be the reaction with the molecule CO itself, whose products are stable at room temperature. Recently, it was shown that a variety of RLi species are able to react with CO or f-BuNC in a newly developed liquid xenon (LXe) cell . LXe was used as reaction medium because it suppresses electron-transfer reactions, which are known to complicate the reaction . In this way the carbonyllithium and acyllithium compounds, as well as the corresponding isolobal isonitrile products, could be characterised by IR spectroscopy for the first time. 

In a first experiment a pressure of 2 bar of CO at — I00°C was applied to a saturated solution of n-BuLi in liquid xenon. Surprisingly, no free CO was detected, but a stretching vibrational mode of the carbonyl adduct of the lithium alkyl was observed at 2047 cm (triple-bonded CO group). Warming up to —30°C led to the appearance of a new v(CO) peak at 1635 cm (double-bonded CO group), while the IR band of the carbonyl adduct vanished. The new absorption was therefore attributed to the acyllithium compound, which also decomposed at slightly higher temperature (—20°C) (equation 1) . ... 

The photocatalytic hydrogenation of alkenes and dienes by Group 6 metal carbonyls has been investigated in LNG solvents [15]. Photolysis of trans-[M(C0)4(C2H4)2] (M = Cr, Mo, W) in liquid xenon doped with H2 leads to formation of mer-[M(CO)3(C2H4)2(q -H2)] and ds-[M(CO)4(C2H4)(q -H2)]. The q -H2 complexes for M = Cr and Mo are much less stable than those for M = W. The evidence supported -coordination of H2 rather than oxidative addition to give dihy-... 

The drift mobility of electrons in nonpolar liquids ranges from high values such as that for liquid xenon of 2000 cm /Vs to low values like that for tetradecane of 0.02 cm /Vs. It has often been suggested that the mobility is high for symmetrical molecules and low for straight chain molecules like -alkanes. Inspection of Table 2 shows that liquids with symmetrical molecules are indeed at the top of the list. However, other less symmetrical molecules like A-trimethylsilylmethane and 2,2,4,4-tetramethylpentane also show high drift mobility. A more important factor may be the existence of many methyl groups in the molecule. In any case, for liquids for which 10 cm /Vs, the electron is considered to be quasi-free. This is supported by the Hall mobility studies, as discussed below. 

Which is more dense liquid xenon or solid xenon ... 

What do you ask in reply to the question At what temperature does liquid xenon begin to boil ... 

Ripmeester (346) used MAS to study xenon adsorbed on zeolites Na-X and H-mordenite. In the case of faujasite containing excess sorbate, separate lines from liquid, solid, gaseous, and sorbed xenon could be distinguished (see Fig. 67). The presence of a line from adsorbed xenon at 160 K shows that sorbed xenon does not freeze at the bulk xenon melting point. The line from liquid xenon measured at 170 K shifts to high field (Fig. 67b), suggesting that sorbed xenon is more dense than bulk liquid. 

---