Xenon physical properties

Pure Elements. AH of the hehum-group elements are colorless, odorless, and tasteless gases at ambient temperature and atmospheric pressure. Chemically, they are nearly inert. A few stable chemical compounds are formed by radon, xenon, and krypton, but none has been reported for neon and belium (see Helium GROUP, compounds). The hehum-group elements are monoatomic and are considered to have perfect spherical symmetry. Because of the theoretical interest generated by this atomic simplicity, the physical properties of ah. the hehum-group elements except radon have been weU studied. 

The physical properties of argon, krypton, and xenon are frequendy selected as standard substances to which the properties of other substances are compared. Examples are the dipole moments, nonspherical shapes, quantum mechanical effects, etc. The principle of corresponding states asserts that the reduced properties of all substances are similar. The reduced properties are dimensionless ratios such as the ratio of a material s temperature to its critical... 

Table 3.3Comparative physical properties of nitrous oxide, xenon and nitric oxide... 

When rebreathing systems are used for the delivery of xenon, its concentration within the system needs to be closely monitored. Infrared gas analysers cannot detect xenon, since it is a single atom, and as it is chemically inert its physical properties must be utilised. Mass spectrometry is the most accurate method but it is expensive and it is impractical for clinical use. A calibrated katharometer combined with a galvanic oxygen sensor is a satisfactory alternative which provides a reasonably accurate measure ( 1%). 

Physical properties of the Xe-PtFt adduct.—The adduct is yellow when deposited in thin films but in bulk is deep red. The solid becomes glassy in appearance when heated to 115°, but does not melt below 165°, when it decomposes to produce xenon tetrafluoride. X-ray powder photographs of the adduct of composition XePtFe show no diffraction pattern. Complex patterns are observed with samples of material richer in platinum. The plasticity of the material made the preparation of good powder samples difficult. Even well-cooled samples did not grind well. 

The existence of simple compounds of the noble gases was first demonstrated in 1962 M. Although it was soon recognized that the binary xenon fluorides, particularly XeF2 and XeF6, could form numerous adducts with fluoride-ion acceptors and, in some cases, with donors, the true nature of the complexes was not fully appreciated at first. Stimulated by the initial surprise at the existence of the compounds, early work was devoted rather to evaluation of the nature of the simple compounds and investigation of their physical properties. 

Within a periodic group the physical properties vary more predictably, especially if the elements are in the same physical state. For example, the melting points of argon and xenon are 189.2°C and 111.9°C, respectively. We can estimate the melting point of the intermediate element krypton by taking the average of these two values as follows ... 

Occurrence, extraction and uses Physical properties Compounds of xenon Compounds of krypton and radon... 

Values extracted and in some cases rounded off from those cited in Rabinovich (ed,), Thermo physical Properties of Neon, Argon, Krypton and Xenon, Standards Press, Moscow, 1976, This source contains values for the compressed state for pressures up to 1000 bar, etc, t = triple point. Above the solid line the condensed phase is solid below it, it is liquid. The notation 5,646,-4 signifies 5,646 x lO"", At 83,8 K, the viscosity of the saturated liquid is 2,93 x 10" Pa S = 0.000293 Ns/m. This book was published in English translation by Hemisphere, New York, 1988 (604 pp,),... 

Photochemical studies on the deterioration of flame-retarded polyester fabrics using a Xenon-arc have been reported and physical properties have been evaluated. ... 

The maximum authorized filling limit for neon, krypton, and xenon in approved types of cylinders is the marked service pressure of the cylinder at 70°F (21.1°C) (or, in the case of specification 3 A and 3AA cylinders meeting additional specified requirements, 10 percent in excess of the marked service pressure). Because commercial grades of xenon deviate markedly in physical properties from the ideal gas at elevated pressures, maximum filling limits for the specific commercial grade of xenon being used must be determined experimentally. 

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