skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A stable compound of helium and sodium at high pressure

Abstract

Helium is generally understood to be chemically inert and this is due to its extremely stable closed-shell electronic configuration, zero electron affinity and an unsurpassed ionization potential. It is not known to form thermodynamically stable compounds, except a few inclusion compounds. Here, using the ab initio evolutionary algorithm USPEX and subsequent high-pressure synthesis in a diamond anvil cell, we report the discovery of a thermodynamically stable compound of helium and sodium, Na 2He, which has a fluorite-type structure and is stable at pressures >113 GPa. We show that the presence of He atoms causes strong electron localization and makes this material insulating. This phase is an electride, with electron pairs localized in interstices, forming eight-centre two-electron bonds within empty Na 8 cubes. We also predict the existence of Na 2HeO with a similar structure at pressures above 15 GPa.

Authors:
; ORCiD logo; ; ; ; ; ; ; ; ; ; ORCiD logo; ; ; ORCiD logo; ;
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States). Advanced Photon Source (APS)
Sponsoring Org.:
National Science Foundation (NSF); Defense Advanced Research Projects Agency (DARPA)
OSTI Identifier:
1355028
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nature Chemistry; Journal Volume: 9; Journal Issue: 5
Country of Publication:
United States
Language:
ENGLISH
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; chemical physics; electron transfer; solid-state chemistry

Citation Formats

Dong, Xiao, Oganov, Artem R., Goncharov, Alexander F., Stavrou, Elissaios, Lobanov, Sergey, Saleh, Gabriele, Qian, Guang-Rui, Zhu, Qiang, Gatti, Carlo, Deringer, Volker L., Dronskowski, Richard, Zhou, Xiang-Feng, Prakapenka, Vitali B., Konôpková, Zuzana, Popov, Ivan A., Boldyrev, Alexander I., and Wang, Hui-Tian. A stable compound of helium and sodium at high pressure. United States: N. p., 2017. Web. doi:10.1038/nchem.2716.
Copy to clipboard
Dong, Xiao, Oganov, Artem R., Goncharov, Alexander F., Stavrou, Elissaios, Lobanov, Sergey, Saleh, Gabriele, Qian, Guang-Rui, Zhu, Qiang, Gatti, Carlo, Deringer, Volker L., Dronskowski, Richard, Zhou, Xiang-Feng, Prakapenka, Vitali B., Konôpková, Zuzana, Popov, Ivan A., Boldyrev, Alexander I., & Wang, Hui-Tian. A stable compound of helium and sodium at high pressure. United States. doi:10.1038/nchem.2716.
Copy to clipboard
Dong, Xiao, Oganov, Artem R., Goncharov, Alexander F., Stavrou, Elissaios, Lobanov, Sergey, Saleh, Gabriele, Qian, Guang-Rui, Zhu, Qiang, Gatti, Carlo, Deringer, Volker L., Dronskowski, Richard, Zhou, Xiang-Feng, Prakapenka, Vitali B., Konôpková, Zuzana, Popov, Ivan A., Boldyrev, Alexander I., and Wang, Hui-Tian. Mon . "A stable compound of helium and sodium at high pressure". United States. doi:10.1038/nchem.2716.
Copy to clipboard
@article{osti_1355028,
title = {A stable compound of helium and sodium at high pressure},
author = {Dong, Xiao and Oganov, Artem R. and Goncharov, Alexander F. and Stavrou, Elissaios and Lobanov, Sergey and Saleh, Gabriele and Qian, Guang-Rui and Zhu, Qiang and Gatti, Carlo and Deringer, Volker L. and Dronskowski, Richard and Zhou, Xiang-Feng and Prakapenka, Vitali B. and Konôpková, Zuzana and Popov, Ivan A. and Boldyrev, Alexander I. and Wang, Hui-Tian},
abstractNote = {Helium is generally understood to be chemically inert and this is due to its extremely stable closed-shell electronic configuration, zero electron affinity and an unsurpassed ionization potential. It is not known to form thermodynamically stable compounds, except a few inclusion compounds. Here, using the ab initio evolutionary algorithm USPEX and subsequent high-pressure synthesis in a diamond anvil cell, we report the discovery of a thermodynamically stable compound of helium and sodium, Na2He, which has a fluorite-type structure and is stable at pressures >113 GPa. We show that the presence of He atoms causes strong electron localization and makes this material insulating. This phase is an electride, with electron pairs localized in interstices, forming eight-centre two-electron bonds within empty Na8 cubes. We also predict the existence of Na2HeO with a similar structure at pressures above 15 GPa.},
doi = {10.1038/nchem.2716},
journal = {Nature Chemistry},
number = 5,
volume = 9,
place = {United States},
year = {Mon Feb 06 00:00:00 EST 2017},
month = {Mon Feb 06 00:00:00 EST 2017}
}
Copy to clipboard
Journal Article:
DOI:  10.1038/nchem.2716
Other availability
Find in Google Scholar Find in Google Scholar
Search WorldCat Search WorldCat to find libraries that may hold this journal
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • ; ; ; ... - Nature Chemistry
    Helium is generally understood to be chemically inert and this is due to its extremely stable closed-shell electronic configuration, zero electron affinity and an unsurpassed ionization potential. It is not known to form thermodynamically stable compounds, except a few inclusion compounds. Here, using the ab initio evolutionary algorithm USPEX and subsequent high-pressure synthesis in a diamond anvil cell, we report the discovery of a thermodynamically stable compound of helium and sodium, Na 2He, which has a fluorite-type structure and is stable at pressures >113 GPa. We show that the presence of He atoms causes strong electron localization and makes thismore » material insulating. This phase is an electride, with electron pairs localized in interstices, forming eight-centre two-electron bonds within empty Na 8 cubes. As a result, we also predict the existence of Na 2HeO with a similar structure at pressures above 15 GPa.« less
    Cited by 20

  • - Electr. Forum; (United States)
    The energy-saving advantages of high-pressure sodium (HPS) systems for roadway lighting are discussed in the context of the popularity of low-pressure (LPS) in Europe and its specification for major lighting and relighting projects in the U.S. A comparison of LPS and HPS lamps notes the larger lamp size and the diminishing lumens per watt of LPS lamps with time and their lower coefficient of utilization. HPS lamps are compact, with more efficiency, better color rendition, and a good maintenance of light output. More useful light actually falls on the roadway with the HPS lamps. Europe, which adopted LPS lamps aftermore » World War II, is the major manufacturer of lamps and luminaire types, although manufacturers are also producing and recommending the HPS lamps.« less

  • ; - Physical Review (U.S.) Superseded in part by Phys. Rev. A, Phys. Rev. B: Solid State, Phys. Rev. C, and Phys. Rev. D
    A high-sensitivity mass spectrometer was used to measure the helium, argon, and neon produced in iron by 0. 16-, 0.43-, and 3.0-Bev protons. The spectrometer has a sensitivity so that 10 /sup -11/ it standard cc of helium could be detected above the contamination level. The He/sup 4/ cross sections are 120 mb, 450 mb, and 1300 mb at 0. 16, 0.43, and 3.0 Bev, respectively, while the He/sup 3/He/sup 4/ cross section ratios are, respectively, 0.09, 0.10, and 0.18. At 0.43 Bev, cross sections of 1.0 mb, 3.3 mb, 8 mb, and 4.1 mb were found for the argonmore » isotopes 36, 37, 38, and 39, respectively. The cross section for neon-21 is 0.1 mb at 0.43 Bev. The results are discussed in relation to evaporation theory and the rare gas coatent of iron meteorites. The He/sup 3/ yields are all higher than previously measured tritium values. At 3 Bev the He/ sup 3/T ratio is 2.4. It is suggested that in the case of iron in evaporation theory the Coulomb barrier is not as important relatively as previously thought. Alternatively, a large fraction of the He/sup 3/ and tritium may be prcduced during the nuclear cascade which precedes the evaporation from the excited nuclei. The cross sections measured bear directly on the cosmicray-produced rare gases in meteorites. From the cross section of directly produced He/sup 3/ relative to T, previous measurements of He/sup 3/-T exposure ages of iron meteorites must be reduced by a factor of about 3. From the argon isotope cross sections it is seen that 50% of the Ar/sup 36/ in meterites is the result of BETA decay of cosmic- ray-produced Cl/sup 36/ and thus Ar/sup 36/-Cl/sup 36/ should be a reliable method for measuring exposure ages of meteorites. (auth)« less

  • ; ; - Physical Review. A
    We perform fully quantum mechanical calculations in the binary approximation of the emission and absorption profiles of the sodium 3s-3p and potassium 4s-4p resonance lines under the influence of a helium perturbing gas. We use carefully constructed potential energy surfaces and transition dipole moments to compute the emission and absorption coefficients at temperatures from 158 to 3000 K. Contributions from quasibound states are included. The resulting red and blue wing profiles agree well with previous theoretical calculations and with experimental measurements.

  • ; ; ; ... - Physical Review Letters
    The Ω phase of the liquid sodium α-Ω dynamo experiment at New Mexico Institute of Mining and Technology in cooperation with Los Alamos National Laboratory has demonstrated a high toroidal field B Φ that is ≃8×B r, where B r is the radial component of an applied poloidal magnetic field. This enhanced toroidal field is produced by the rotational shear in stable Couette flow within liquid sodium at a magnetic Reynolds number Rm≃120. Small turbulence in stable Taylor-Couette flow is caused by Ekman flow at the end walls, which causes an estimated turbulence energy fraction of (δv/v) 2~10 -3.