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Isotopic enrichment

Nature Chemistry volume 11, pages 101–102 (2019)Cite this article

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Michelle Francl suggests that we should expand our view of the periodic table to new dimensions.

It happens every year, without fail. “What is the mass of the chlorine atom?” I ask my quantum mechanics students as we work out the classic problem of the harmonic vibration of H35Cl. Out come the periodic tables — on smartphones rather than paper these days. “35.45!” Not quite, I remind them — that’s the average terrestrial atomic mass. If this class were being held on the moon1 the conventional mass of chlorine on the periodic table would be 35.46 atomic mass units. Do they think the fundamental vibrational frequency of a diatomic molecule would depend on the location in the solar system? They agree it doesn’t and we turn to a discussion of exact isotopic masses and why they aren’t whole numbers or averages — and where to look them up.

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Fig. 1: Elements and isotopes.

CIAAW

Fig. 2: Two views of the 3,380 identified isotopes of the elements, stacked on the periodic table.

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Authors and Affiliations

  1. Department of Chemistry, Bryn Mawr College, Bryn Mawr, PA, USA

    Michelle Francl

  2. Vatican Observatory, Vatican City, Vatican City State

    Michelle Francl

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  1. Michelle Francl
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Correspondence to Michelle Francl.

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Twitter: @MichelleFrancl

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Francl, M. Isotopic enrichment. Nature Chem 11, 101–102 (2019). https://doi.org/10.1038/s41557-018-0206-5

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