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Molecular isotope decays

  1. May 3, 2010 #1
    I understand half-lives, how various atoms decay through the various types of emissions (alpha, beta, gamma, etc).

    It's easy to do the math (or read the decay chain) for various things to see what the end-stable result if (eg U-238 and 235 decay to a thorium isotope, eventually to lead).

    However, what happens when the decay involves a moluecule ? eg uranium hexa-flouride (UF6), does that become ThF6 when a decay event happens ? Or say NaI with I-129, where the iodine decays in to xenon. Surely you don't get NaXe ?

    I wonder if an ionic molecule like NaI would be different from a non-ionic like UF6 based on the bonds.

    I dug out my old Oxtoby & Nash text book and it only covers single atom/element decay, and various searches on google and wiki don't answer this side of nuclear decay (though I may be using the wrong terms). Also searched the archives here, but again may be using the wrong terms.
  2. jcsd
  3. May 5, 2010 #2


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    Staff: Mentor

    Decay doesn't "involve a molecule". What decays is always an atom. Note, that recoil can throw nucleus away from the molecule and that in most cases decay products will ionize surrounding atoms. That basically means that final product of the change will be completely different from the initial substance. It can be to some extent predicted using chemical properties of the elements involved - as you have correctly stated there is no compound like NaXe, so after Na129I decay (of the sample large enough, kept isolated from other elements/substances) you will probably end with metallic sodium and xenon.

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