Extinction in X-Ray Crystallography

Kathleen Lonsdale
Reader in Crystallography, University College, London.

Summary: The total absorption and the total scattering from a single crystal or from a crystalline powder are both affected, by primary and secondary extinction, to an extent which varies with crystal texture. The dependence of each on wave-length of X-rays, on perfect crystallite size, and on over-all size of specimen is considered. It is concluded that secondary extinction for a fine powder is greater than that for a coarse powder and that the linear absorption coefficient measured on powdered briquettes or on metal foil is not the correct value to use for single crystal work. Divergent beam transmission photographs give much qualitative information about crystal texture.

Mineralogical Magazine; March 1947 v. 28; no. 196; p. 14-25; DOI: 10.1180/minmag.1947.028.196.04
© 1947, The Mineralogical Society
Mineralogical Society (www.minersoc.org)