Posts Tagged ‘helium’

Hypervalent Helium – not!

Friday, February 16th, 2018
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Last year, this article[1] attracted a lot of attention as the first example of molecular helium in the form of Na2He. In fact, the helium in this species has a calculated bond index of only 0.15 and it is better classified as a sodium electride with the ionisation induced by pressure and the presence of helium atoms. The helium is neither valent, nor indeed hypervalent (the meanings are in fact equivalent for this element). In a separate blog posted in 2013, I noted a cobalt carbonyl complex containing a hexacoordinate hydrogen in the form of hydride, H. A comment appended to this blog insightfully asked about the isoelectronic complex containing He instead of H. Here, rather belatedly, I respond to this comment!

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References

  1. X. Dong, A.R. Oganov, A.F. Goncharov, E. Stavrou, S. Lobanov, G. Saleh, G. Qian, Q. Zhu, C. Gatti, V.L. Deringer, R. Dronskowski, X. Zhou, V.B. Prakapenka, Z. Konôpková, I.A. Popov, A.I. Boldyrev, and H. Wang, "A stable compound of helium and sodium at high pressure", Nature Chemistry, vol. 9, pp. 440-445, 2017. http://dx.doi.org/10.1038/nchem.2716

Na2He: a stable compound of helium and sodium at high pressure.

Saturday, February 11th, 2017
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On February 6th I was alerted to this intriguing article[1] by a phone call, made 55 minutes before the article embargo was due to be released. Gizmodo wanted to know if I could provide an (almost) instant quote. After a few days, this report of a stable compound of helium and sodium still seems impressive to me and I now impart a few more thoughts here.

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References

  1. X. Dong, A.R. Oganov, A.F. Goncharov, E. Stavrou, S. Lobanov, G. Saleh, G. Qian, Q. Zhu, C. Gatti, V.L. Deringer, R. Dronskowski, X. Zhou, V.B. Prakapenka, Z. Konôpková, I.A. Popov, A.I. Boldyrev, and H. Wang, "A stable compound of helium and sodium at high pressure", Nature Chemistry, vol. 9, pp. 440-445, 2017. http://dx.doi.org/10.1038/nchem.2716

To blog or to publish. That is the question.

Tuesday, February 9th, 2010
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Scientists write blogs for a variety of reasons. But these do probably not include getting tenure (or grants). For that one has to publish. And I will argue here that a blog is not currently accepted as a scientific publication (for more discussion on this point, see this article by Maureen Pennock and Richard Davis). For chemists, publication means in a relatively small number of high-impact journals. Anything more than five articles a year in such journals, and your tenure is (probably) secure (if not your funding).

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