The effects of extinction on the refined structural parameters of crystalline BeO: A neutron and γ-ray diffraction study

Neutron and γ-ray diffraction data collected from the same single crystal of BeO were used in conventional crystal structure refinements. The very severely extinguished neutron data are adequately modeled with the Becker-Coppens anisotropic-extinction formalism. Although the thermal parameters are unreliable, the positional parameter is close to the best estimate obtained from the γ-ray results. The γ-ray (103 keV) data are much less extinguished than the neutron data. Refinements utilizing high-order γ-ray data with neutral-atom and spherical generalized scattering factors are virtually identical. (orig.)