Laue class
From Online Dictionary of Crystallography
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Revision as of 08:02, 25 June 2006 by AndreAuthier (talk | contribs)
Classes de Laue (Fr). Laue Klassen (Ge). Clases de Laue (Sp). Classi di Laue (It)
Definition
The Laue classes correspond to the eleven centrosymmetric crystallographic point groups. When absorption is negligible and Friedel's law applies, it is impossible to distinguish by diffraction between a centrosymmetric point group and one of its non-centrosymmetric subgroups.
Laue classes | Non-centrosymmetric groups having the same Laue class |
[math]{\bar 1}[/math] | 1 |
2/m | 2, m |
mmm | 222, 2mm |
[math]{\bar 3}[/math] | 3 |
[math]{\bar 3}m[/math] | 32, 3m |
4/m | 4, [math]{\bar 4}[/math] |
4/mmm | 422, [math]{\bar 4}2m[/math], 42m |
6/m | 6, [math]{\bar 6}[/math] |
6/mmm | 622, [math]{\bar 6}2m[/math], 62m |
[math]m{\bar 3}[/math] | 23 |
[math]m{\bar 3}m[/math] | 432, [math]{\bar 4}[/math]32 |
See also
Chapter 3.1 of International Tables of Crystallography, Section A
Chapter 2.4 of International Tables of Crystallography, Section D