Laue class

From Online Dictionary of Crystallography

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<font color="blue">Classe de Laue</font> (''Fr''). <font color="red">Laue-Klasse</font> (''Ge''). <font color="black">Classi di Laue</font>(''It''). <font color="purple">ラウエ結晶類</font>(''Ja''). <font color="green">Clase de Laue</font> (''Sp'').
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<font color="blue">Classe de Laue</font> (''Fr''). <font color="red">Laue-Klasse</font> (''Ge''). <font color="black">Classi di Laue</font>(''It''). <font color="purple">ラウエ群</font>(''Ja''). <font color="green">Clase de Laue</font> (''Sp'').

Revision as of 13:59, 26 March 2019

Classe de Laue (Fr). Laue-Klasse (Ge). Classi di Laue(It). ラウエ群(Ja). Clase de Laue (Sp).


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