Nuclear magnetic resonance (NMR) spectroscopy has far-reaching applications in many scientific fields, particularly in chemical structure determination. Although we’ll just give an overview of the subject in this chapter, focusing on NMR applications with small molecules, more advanced NMR techniques are also used in biological chemistry to study protein structure and folding. Nuclear magnetic resonance (NMR) spectroscopy is the most valuable spectroscopic technique available to organic chemists. It’s the method of structure determination that organic chemists usually turn to first. We saw in the chapter on Structure Determination: Mass Spectrometry and Infrared Spectroscopy that mass spectrometry gives a molecule’s formula and infrared spectroscopy identifies a molecule’s functional groups. Nuclear magnetic resonance spectroscopy complements these other techniques by mapping a molecule’s carbon–hydrogen framework. Taken together, MS, IR, and NMR make it possible to determine the structures of even very complex molecules. 0 1 Mass spectrometry Molecular size and formula Infrared spectroscopy Functional groups present NMR spectroscopy Map of carbon–hydrogen framework