Nuclei other than Protons:

You would recall that only those nuclei show NMR that have nuclear spin angular momentum quantum number, I ≥ ½ . More than 200 isotopes in principle can be studied through NMR. Of these, ¹³C, ¹⁹F or ³¹P are most hugely used besides ¹H. The characteristics of these nuclei are given in Table. In many organic compounds where proton magnetic resonance spectrum does not provide unambiguous information and carbon-13 NMR spectra have been found to be especially useful for structure elucidation. ¹³C NMR spectra are intrinsically much less sensitive than proton NMR spectrum. The low signal strength gives output from the fact in which the natural abundance of ¹³C is only 1.11% and also its magnetic moment is ¼ th of that of the proton in a given magnetic field.

Table:  Characteristics of some nuclei commonly exploited in NMR

Besides ¹³C, two other most widely investigated nuclei are ¹⁹F and ³¹P, both of which not only have I = ½ but both of these nuclei have natural abundance of 100%. In these cases NMR spectra can be analysed in terms of their characteristic chemical shift (δ) and spin-spin coupling constants (J) due to their interaction with other nuclei. In addition to these, other nuclei like as ²D, ¹¹B, ¹⁵N, ²⁹S1, ²³Na, ¹⁰⁹Ag, ¹⁹⁹Hg, ¹¹³Cd and ²⁰⁷Pb have also been investigated. NMR of those nuclei is particularly significant in the field of Organic Chemistry, Biochemistry, Biology, Organometallic Chemistry, alloys and intermetallic compounds.