Laue classes

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Classes de Laue (Fr). Laue Klassen (Ge). Clases de Laue (Sp). Classi di Laue (It). ラウエ結晶類(Ja).


Definition

The Laue classes are eleven geometric crystal classes containing centrosymmetric crystallographic types of point groups and their subgroups. 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; only point groups belonging to different Laue classes can then be distinguished.


Laue classesNon-centrosymmetric groups
in the same Laue class
{\bar 1} 1
2/m 2, m
mmm 222, 2mm
{\bar 3} 3
{\bar 3}m 32, 3m
4/m 4, {\bar 4}
4/mmm 422, {\bar 4}2m, 4mm
6/m 6, {\bar 6}
6/mmm 622, {\bar 6}2m, 6mm
m{\bar 3} 23
m{\bar 3}m 432, {\bar 4}32

See also

  • Chapter 1.6 of International Tables for Crystallography, Section A, 6th edition
  • Chapter 2.4 of International Tables for Crystallography, Section D