I ask this b/c I know the NMR deal with magnetic fields (MF) and it can change energy of proton’s magnetic energy. But my question is that electrons also have a spin and M F. Just like how IR and Mass deal with electrons, why don’t NMR also talk about electrons? Why just focus in the nucleus.

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    $\begingroup$ The energy gap between "up" and "down" spin states of an electron is much larger than the energy gap between the two spin states of a proton. So, the spectra don't quite interfere. It is possible to do what is essentially NMR, but on an electron: en.wikipedia.org/wiki/Electron_paramagnetic_resonance $\endgroup$ Feb 10, 2017 at 21:51
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    $\begingroup$ Your question and title are inconsistent. All nuclei aren't just a proton. $\ce{^13C}$ is also used for NMR studies as well as other isotopes. $\endgroup$
    – MaxW
    Feb 10, 2017 at 21:52
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    $\begingroup$ Electron spins are used for spectroscopy. The expected energy gap is different so you would be looking in a different area of the EM spectrum (i.e., microwave versus radio). See: en.wikipedia.org/wiki/Electron_paramagnetic_resonance $\endgroup$
    – Zhe
    Feb 10, 2017 at 23:07
  • $\begingroup$ So can I know why electron spin are also not used to know a molecules structure in orgo? Why just focus on NMR? Does NMR have more usefulness? $\endgroup$
    – TLo
    Feb 11, 2017 at 0:12
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    $\begingroup$ EPR only works for unpaired electrons. Most organic compounds have only paired electrons. Organometallic complexes are fairly rare in the overall scheme of things. $\endgroup$
    – MaxW
    Feb 11, 2017 at 2:56

1 Answer 1


NMR deals with the nucleus of an atom (not just protons, but all nuclear isotopes with spin>0). Electrons also have a magnetic moment, and the technique used to probe this phenomenon is EPR/ESR. While NMR uses frequency in the MHz range (MHz), ESR uses higher energies in GHz range.

Lots of common references available on the internet to learn more, but you might be interested in:


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