Nuclear magnetic resonance (NMR) is a phenomenon exhibited by certain nuclei that can absorb characteristic radio frequency radiation under certain conditions. NMR has been extensively applied in molecular spectroscopy and medical diagnostic imaging. In both these applications, the molecule or subject under study is placed in a magnetic field and irradiated with radio frequency energy.

NMR spectroscopy generates a spectrum where the characteristic absorption frequencies of the sample are plotted against the peak intensities. The NMR spectrum provides detailed information about the electronic environments of atoms in the sample. Interpretation of the spectrum can help to identify molecular structures of organic compounds and biological macromolecules, as well as understand dynamic processes alongside reaction kinetics.

In medicine, magnetic resonance imaging, commonly called MRI, is a noninvasive imaging technique that avoids the use of harmful radiation. MRI uses NMR to generate detailed images of internal organs and tissues.