Our chemistry teacher taught us last year, that radioactive isotopes of elements don't form compounds with other elements "because they're unstable" and since we're high-schoolers (I'm assuming that's why) she didn't go into details.

But today in our Biology class, we were taught about the Hershey-Chase experiment (https://en.wikipedia.org/wiki/Hershey%E2%80%93Chase_experiment) , where we come across radioactive P-32 being incorporated into the phosphate group of nucleic acids and radioactive S-35 being incorporated into amino acids in proteins.

When we reached that bit, what our Chem. teacher said came back to me and it conflicted with the idea being propounded in class. Naturally I raised that issue with our Bio teacher, but she said she wasn't sure about' radioactive isotopes not forming chemical bonds', because that was precisely what was happening in the Hershey-Chase experiment.

So can anyone tell me whether:

a) My Chem. teacher was correct (perhaps within limits), and that the incorporation of radioactive isotopes in nucleic acids and proteins is a phenomenon that occurs outside of the limiting case she mentioned.

b) My Bio. teacher was right. Radioactive isotopes do form compounds.

c) None of the above (could you specify why?)

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    $\begingroup$ Your Chem. teacher is quite definitely wrong. Radioactive isotopes surely do form compounds; in fact, they form the same compounds as normal isotopes would. They don't differ from normal isotopes at all, except that they are radioactive. Why else isotope separation would be such a trouble? $\endgroup$ Commented Aug 31, 2016 at 8:19
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    $\begingroup$ I am radiochemsit, actually your teacher is wrong. Radioactive isotope do form chemical bond with other compound. Very simple example is 2-deoxy-2-(18F)fluoro-D-glucose is a glucose analogue used as Positron imaging agent (PET). $\endgroup$
    – Khan
    Commented Aug 31, 2016 at 8:35
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    $\begingroup$ Multiple elements don't even have any stable isotopes and so every atom of the element is necessarily radioactive, yet they still form an abundance of compounds. A simple example would be uranium. $\endgroup$ Commented Aug 31, 2016 at 9:19

1 Answer 1


Radioactive isotopes have similar chemical properties to that of nonradioactive element of same atom. They actually do from chemical bond with compound. You even heard the name of radio-pharmaceutical that involved the complex of radioactive metal with ligand or the radioactive isotope is attached to the pharmaceutical through covalent bond.

The simplest example is FDG is 18F-labled glucose analogue.

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Carbon-11 is another radioactive isotope that form covalent bond similar to Carbon-12 and used in Nuclear medicine as PET imaging agent. C11-Methionine is an example used in the field of Nuclear Medicine for the diagnosis of brain tumour

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Iodine-131 is another sample of radioactive isotope that is used for the detection of hypothyroidism and also form bond with compound. Like in metaiodobenzylguanidine is used in neuroblastoma

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I can gave you lots of others examples but i think these are enough for your understanding. I hope, this will be helpful.

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    $\begingroup$ Or, even simpler - how could anybody mine uranium ore (an oxide) if radioactive isotopes did not form compounds - all of the uranium isotopes are unstable. $\endgroup$
    – Jon Custer
    Commented Aug 31, 2016 at 12:43

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