# What other nuclei besides hydrogen and carbon 13 could be detected using NMR and is H1-NMR synonymus to NMR?

From my understanding NMR spectroscopy works by analyzing the resonance frequency of each structure around a hydrogen or carbon. Since every structure is unique and has unique resonance frequency it is easy to identify them. Is this correct?

What other nuclei besides hydrogen and carbon 13 could be detected using NMR?

Is H1 NMR the same as saying NMR?

• Have you used a common web-based search engine to research this question? Try reading this wikipedia page. – long Oct 27 '14 at 23:39

The term $$\ce{^1H}$$ NMR is more specific than the term "NMR" in that it is referring only to NMR experiments involving protons. It is usually relatively straight forward to identify which atom in a molecule is responsible for a certain NMR signal. There is also a lot of other information that can be extracted from an NMR signal by doing secondary NMR experiments that can help with peak assignment. That said, some molecules are so large and complex that signal assignment can become problematical. As to which other nuclei can be detected by NMR, any isotope with an odd number of protons and/or neutrons will have a magnetic moment and be detectable by the NMR experiment. Here is a listing of some nuclei with non-zero spin that have been studied by NMR (see this Wikipedia article): $$\ce{^1H}$$, $$\ce{^2H}$$, $$\ce{^6Li}$$, $$\ce{^10B}$$, $$\ce{^11B}$$, $$\ce{^13C}$$, $$\ce{^14N}$$, $$\ce{^15N}$$, $$\ce{^17O}$$, $$\ce{^19F}$$, $$\ce{^23Na}$$, $$\ce{^29Si}$$, $$\ce{^31P}$$, $$\ce{^35Cl}$$, $$\ce{^113Cd}$$, $$\ce{^129Xe}$$, $$\ce{^195Pt}$$.

It's not always easy to interpret NMR spectra. Different nuclei can show the same chemical shift, leading to overlapping signals. NMR signals are also not infinitely sharp, overlapping signals are rather common.

But there are also more advanced experiments you can use to solve these issues, if you have enough of your sample and enough time on a spectrometer.

1H NMR is the most common type because 1H is almost 100% abundant, and hydrogens are present in most organic compounds. 13C and 15N are also used often because they are common in organic chemistry and especially in biology. Those isotopes are rather rare in nature though, this makes experiments involving them much, much less sensitive than proton NMR. If you want to perform more complicated experiments with these nuclei you have to isotope-label your sample, which is routinely done for proteins, but extremely expensive or even impossible for small organic molecules.

19F is another isotope that works well for NMR, it is also around 100% abundant and therefore very sensitive.

In general, you can do NMR on any spin 1/2 nucleus. Nuclei with higher spins is also possible, but that gets more difficult.

Since every structure is unique and has unique resonance frequency it is easy to identify them.

Firstly, in NMR we do not deal with structures, but instead nuclei. Scroll all the way to the bottom to see a list of some NMR active nuclei on the website of Hans J. Reich (University of Wisconsin): Summary of Nuclear Properties.

You'll note that some are listed as having low sensitivity which is related to certain properties which we won't go into.

The good thing about NMR, from an organic chemistry point of view at least, is that carbon has only one NMR active nuclei, $$\ce{^{13}C}$$, that additionally has very low abundance $$(\approx1\%)$$. Hence, when you perform a $$\ce{^1H}$$ NMR experiment on an organic molecule like ethanol, for example, you are unlikely to see carbon nuclei interacting and causing splitting.

You may ask how we obtain $$\ce{^{13}C}$$ NMR spectra? Well, it is possible, just not easy. Beyond having very low abundance it also possesses a long relaxation time which essentially means that when you excite a $$\ce{^{13}C}$$ nuclei there is a long period of time that elapses before it relaxes back to the ground state and is capable of being excited again to obtain a clean spectra.