ISSN:
1600-5724
Quelle:
Crystallography Journals Online : IUCR Backfile Archive 1948-2001
Thema:
Chemie und Pharmazie
,
Geologie und Paläontologie
,
Physik
Notizen:
An investigation has been made of some large anisotropies observed in the X-ray scattering from a single crystal of Cr-Cl boracite, Cr3B7O13Cl, in its room-temperature cubic phase. The model of Coppens & Hamilton [Acta Cryst. (1970), A26, 71-83] for anisotropic secondary extinction has been used to describe the results. Both the type I (domain misorientation) and the type II (domain shape) extinction of that model were found to be present. A new expression for the orientation dependence of type I extinction is introduced, which is believed to be more appropriate to the normal experimental situation. With this modification, the model was able to reproduce fairly well the observed changes in integrated intensity on rotation about the scattering vector. The components of the tensors describing the two types of extinction indicated much greater angular misorientation about the growth axis of the crystal than perpendicular to it, and a domain semi-axis smaller along the growth axis than perpendicular to it.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1107/S0567739474001823
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