What is NMR?

NMR stands for Nuclear Magnetic Resonance and it is one of the most powerful tools for determining molecular structure.

The NMR spectrum of an organic compound provides information concerning:

How Does NMR Work?

    NMR is a phenomenon which occurs when the nuclei of certain atoms are immersed in a static magnetic field and exposed  to a second oscillating magnetic field.  In proton NMR, positively charged protons (hydrogen atoms) are in constant motion. When they are placed in magnetic field they become magnets too.  Naturally, magnets line up in a magnetic field in the opposite direction of the field, so the proton will line up in the opposite direction of the magnetic field.  Then, when radio wave energy is emitted by the NMR machine it causes the magnet (proton) to switch direction. When this happens, the radio energy is absorbed by the proton.  The absorption is detected by the detector.  This results in a peak in the NMR spectrum.
Figure 1. This graphic displays a schematic representation of the major systems of a nuclear magnetic resonance spectrometer and a few of the major interconnections.  This image was taken from  Joseph P. Hornak, Ph.D.'s web site, The Basics of NMR