Standard Article

Electron Paramagnetic Resonance

Resonance Methods

  1. Gareth R. Eaton,
  2. Sandra S. Eaton

Published Online: 18 MAY 2012

DOI: 10.1002/0471266965.com067.pub2

Characterization of Materials

Characterization of Materials

How to Cite

Eaton, G. R. and Eaton, S. S. 2012. Electron Paramagnetic Resonance. Characterization of Materials. 1–13.

Author Information

  1. University of Denver, Department of Chemistry and Biochemistry, Denver, CO, USA

Publication History

  1. Published Online: 18 MAY 2012


Electron paramagnetic resonance (EPR), also known as electron spin resonance (ESR) or electron magnetic resonance (EMR), is the method of choice for characterizing unpaired electrons in materials. With proper attention to experimental methods, EPR can provide quantitation of the concentrations of unpaired electrons and characterize the chemical environment of the spin. It is routinely applied to solid or liquid samples. Cryogenic temperatures may be needed to observe transition metal ions with rapid electron spin relaxation.


  • electron spin;
  • organic radical;
  • metal ion;
  • unpaired electron