X-ray diffraction

Article By:

Mantler, Michael Technical University of Vienna, Vienna, Austria.

Last reviewed:April 2022

DOI:https://doi.org/10.1036/1097-8542.750600

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• X-ray diffraction, published January 2014:Download PDF Get Adobe Acrobat Reader

The scattering of x-rays by matter with accompanying variation in intensity for specific directions (or wavelengths) due to interference effects. X-ray diffraction is a powerful and readily available method for determining atomic arrangements in matter and thereby one of the most important tools of solid-state physics and chemistry. The method depends upon the fact that x-ray wavelengths of the order of one nanometer are readily available and that this is the same order of magnitude of crystalline unit cells (that is, the periodic atomic structure unit by which crystals are built). When an x-ray beam falls on matter, scattered x-radiation is produced and spreads out spherically from the electronic shells of all the atoms in the sample. The interference effects of the coherently scattered radiation from the different crystalline unit cells cause the intensity of the scattered radiation to exhibit maxima and minima in various directions (Fig. 1). These patterns represent the crystal structure, while the relative intensities of their peaks depend also on the kind and arrangement of atoms within the unit cells. See also: Diffraction; X-ray crystallography

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