EXAFS: new horizons in structure determinations.

Although the phenomena of extended x=ray absorption fine structure (EXAFS) were observed as early as the 1930's, EXAFS has only recently, with the utilization of synchrotron radiation, been transformed into a powerful structural technique. The theory and experimental practice of the technique are described and illustrated with data on germanium. Applications to systems as diverse as hemoglobin, polymer-bound catalysts, ions in solution, amorphous solids, and adsorbate atoms on surfaces are reviewed. With the recent approval of funding for new, more powerful dedicated synchrotron sources, the future holds the possibility of a virtual revolution in structure determinations.