A high-pressure van der Waals compound in solid nitrogen-helium mixtures


WEAKLY bound van der Waals molecules, consisting of atoms or molecules (such as rare gases, H2 and N2) interacting through van der Waals forces, can be formed in the gas phase1. The existence of similar weakly bound stoichiometric compounds in condensed phases has remained an open question as the components usually form separate pure phases or solid solutions2. Here we report on a detailed study of the helium–nitrogen system in a diamond-anvil cell using synchrotron X-ray diffraction, Raman scattering and optical microscopy. We find that high pressure stabilizes the formation of a stoichiometric, solid van der Waals compound of composition He(N2)11. Because of the relatively simple interactions involved, this solid may exemplify a novel class of van der Waals compounds that are formed only at high pressures. Van der Waals chemistry in simple molecular systems may be important for understanding the structure and properties of the interiors of the outer planets and their satellites, where pressures are high and such components may be abundant3–5.

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  1. 1

    Novick, S. E., Leopold, K. R. & Klemperer, W. in Atomic and Molecular Clusters (ed. Bernstein, E. R.) 359–391 (Elsevier, New York, 1990).

  2. 2

    Meyer, L. Adv. chem. Phys. 16, 343–387 (1969).

  3. 3

    Hubbard, W. B. Planetary Interiors (van Nostrand, New York, 1984).

  4. 4

    Nellis, W. J. et al. Science 240, 779–781 (1988).

  5. 5

    Hubbard, W. B. et al. Science 253, 648–651 (1991).

  6. 6

    Schouten, J. A. Phys. Rep. 172, 33–92 (1989).

  7. 7

    Schouten, J. A. Fluid Phase Equil. (in the press).

  8. 8

    Cromer, D. T., Mills, R. L., Schiferl, D. & Schwalbe, L. A. Acta crystallogr. B37, 8–11 (1981).

  9. 9

    Mills, R. L., Cromer, D. T. & Olinger, B. J. chem. Phys. 84, 2837–2845 (1986).

  10. 10

    Olijnyk, H. J. chem. Phys 93, 8968–8972 (1990).

  11. 11

    Vos, W. L., van Hinsberg, M. G. E. & Schouten, J. A. Phys. Rev. B42, 6106–6109 (1990).

  12. 12

    Mao, H. K. et al. Phys. Rev. Lett. 60, 2649–2652 (1988).

  13. 13

    Vos, W. L. & Schouten, J. A. Phys. Rev. Lett. 64, 898–901 (1990).

  14. 14

    Scheerboom, M. I. M. & Schouten, J. A. J. Phys.: Condensed Matter 3, 8305–8312 (1991).

  15. 15

    Vos, W. L. & Schouten, J. A. Physica A182, 365–387 (1992).

  16. 16

    van den Bergh, L. C., Schouten, J. A. & Trappeniers, N. J. Physica A141, 524–538 (1987).

  17. 17

    Mao, H. K. et al. Science 239, 1131–1134 (1988).

  18. 18

    Le Toullec, R., Loubeyre, P. & Pinceaux, J.-P. Phys. Rev. B40, 2368–2378 (1990).

  19. 19

    van den Bergh, L. C. & Schouten, J. A. J. chem. Phys. 89, 2336–2343 (1988).

  20. 20

    Bartlett P. J. Phys.: Condensed Matter 2, 4979–4989 (1990).

  21. 21

    Murray, M. J. & Sanders, J. V. Phil. Mag. A42, 721–740 (1980).

  22. 22

    Kitaigorodsky, A. I. Mixed Crystals (Springer, Berlin, 1984).

  23. 23

    Hemley, R. J. & Mao, H. K. in Proc. APS 1991 Topical Conf. Shock Compression of Condensed Matter (eds Schmidt, S. C., Dick, R. D., Forbes, J. W. & Tasker, D. G.) (in the press).

  24. 24

    Mao, H. K. in Simple Molecular Systems at Very High Densities (eds Polian, A., Loubeyre, P. & Boccara, N.) 221–236 (Plenum, New York, 1989).

  25. 25

    Hu, J. Z., Mao, H. K. & Shu, J. F. EOS 72, 554 (1991).

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Vos, W., Finger, L., Hemley, R. et al. A high-pressure van der Waals compound in solid nitrogen-helium mixtures. Nature 358, 46–48 (1992). https://doi.org/10.1038/358046a0

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