Noble Gas Elements Research Articles

Inert gas abundances in basalts of the Lesser Antilles island arcs: possible implications for their volcanic evolution

Measurements of noble gas element abundances in igneous rock samples from the Lesser Antilles island arc (LAIA) show an enrichment of Ne, Kr and Xe relative to Ar, when compared to the atmospheric inert gas composition. The element concentrations vary as a function of time and a cyclic variation appears to occur in the pre-Pliocene stage of arc development. The pattern of elemental abundances closely resembles that of ocean floor basalts, suggesting that, (1) the origin of the inert gases in these samples is related to the subduction of oceanic lithosphere responsible for the formation of the LAIA, and (2) the subduction process does not modify the noble gas patterns of the materials being subducted. There is no evidence of a change in concentration or composition of noble gases occurring at ca. 9 Ma, the time when it has been suggested the LAIA shifted to form the western, younger, volcanic Caribbees. However, a major hiatus in the noble gas evolution is recognised at ca. 16 Ma.

A novel isol ion source

A new plasma ion source of Nielsen-type geometry is described permitting operation as normal arc discharge, forced electron beam induced arc discharge or as surface ionization source. Off-line and on-line performances with halogen, noble gas and alkali elements are discussed.

Neil Bartlett wins Welch Award

Dr. Neil Bartlett, the chemist who made the first compound containing a noble gas element, will be awarded the Robert A. Welch Award in Chemistry. The $100,000 award and gold medal is given biennially by the Robert A. Welch Foundation at its annual conference on chemical research. This year's conference will be held in Houston beginning Nov. 8. Bartlett is the third winner of the award, which was established in 1972 to recognize in a substantial manner the value of chemical research with respect to the betterment of mankind. He is a professor of chemistry at the University of California, Berkeley, and a principal investigator at Lawrence Berkeley Laboratory. Although oxidation potentials for the noble gas elements had been determined before Bartlett's experiments, it was held an established law of chemistry that elements with an octet of electrons in their outer electron shell did not react. Bartlett, then at the University of British Columbia, felt ...

Recent advances in the chemistry of noble gas elements

Recent advances in the chemistry of noble gas elements

Growth responses of Neurospora crassa to increased partial pressures of the noble gases and nitrogen.

Buchheit, R. G. (Union Carbide Corp., Tonawanda, N.Y.), H. R. Schreiner, and G. F. Doebbler. Growth responses of Neurospora crassa to increased partial pressures of the noble gases and nitrogen. J. Bacteriol. 91:622-627. 1966.-Growth rate of the fungus Neurospora crassa depends in part on the nature of metabolically "inert gas" present in its environment. At high partial pressures, the noble gas elements (helium, neon, argon, krypton, and xenon) inhibit growth in the order: Xe > Kr> Ar >> Ne >> He. Nitrogen (N(2)) closely resembles He in inhibitory effectiveness. Partial pressures required for 50% inhibition of growth were: Xe (0.8 atm), Kr (1.6 atm), Ar (3.8 atm), Ne (35 atm), and He ( approximately 300 atm). With respect to inhibition of growth, the noble gases and N(2) differ qualitatively and quantitatively from the order of effectiveness found with other biological effects, i.e., narcosis, inhibition of insect development, depression of O(2)-dependent radiation sensitivity, and effects on tissue-slice glycolysis and respiration. Partial pressures giving 50% inhibition of N. crassa growth parallel various physical properties (i.e., solubilities, solubility ratios, etc.) of the noble gases. Linear correlation of 50% inhibition pressures to the polarizability and of the logarithm of pressure to the first and second ionization potentials suggests the involvement of weak intermolecular interactions or charge-transfer in the biological activity of the noble gases.

Covalent Radii of Noble Gas Atoms and Position of Hydrogen in the Periodic System of Elements

IN connexion with the discussion initiated in the article by Dash1 on the position of hydrogen in the periodic system of elements, I wish to say that one cannot disagree with the critical notice of Hawes2, who has stressed that it is not correct to express the ‘atomic size’ of members of the noble gas family in terms of their van der Waals radii (the only radii which are conveniently measurable) while for other elements (in the comparisons presented by Dash) covalent or metallic radii are used. Although, as Dash3 has stated in his reply, the noble gas elements do not form homopolar covalent aggregates, the discovery during 1962–64 of a large number of noble gas compounds makes possible nowadays the estimation of covalent radii for these elements on the basis of their heteroatomic compounds, Such an attempt has been made by myself and colleagues4.

Hartree Calculations for the Ground State of Solid He and other Noble Gas Crystals

A single-particle model in which the wave functions are spherically symmetric about each lattice site was used to calculate the ground-state energy ${E}_{0}$ of solid He. The self-consistent Hartree equations (which yielded the best such wave functions) were solved numerically to an accuracy of better than 1%. The results were worse than could have been expected a priori: At the observed densities, the calculated values of ${E}_{0}$ were approximately +34 and +14 cal/mole for ${\mathrm{He}}^{3}$ and ${\mathrm{He}}^{4}$, respectively, as compared with experimental values of -4.5 and -12 cal/mole. Previous calculations are discussed in the light of our results. In addition, we calculated ${E}_{0}$ for the crystals of the other noble gas elements. The results for Ar, Kr, and Xe are within experimental error whereas ${\mathrm{E}}_{0}$ for Ne is definitely outside this error (being about 5% higher than experiment).