Difference between revisions of "Fixed-point-free space group"
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[[Space group]]s with no special [[Wyckoff position]]s (''i.e''. with no special [[crystallographic orbit]]s) are called '''fixed-point-free space groups''' or '''torsion-free space groups''' or '''Bieberbach groups'''. In fixed-point-free space groups every element other than the identity has infinite order. | [[Space group]]s with no special [[Wyckoff position]]s (''i.e''. with no special [[crystallographic orbit]]s) are called '''fixed-point-free space groups''' or '''torsion-free space groups''' or '''Bieberbach groups'''. In fixed-point-free space groups every element other than the identity has infinite order. | ||
Revision as of 13:33, 13 November 2017
Fixpunktfreie Raumgruppe, Bieberbachgruppe (Ge). Grupo espacial sin puntos fijos (Sp).
Space groups with no special Wyckoff positions (i.e. with no special crystallographic orbits) are called fixed-point-free space groups or torsion-free space groups or Bieberbach groups. In fixed-point-free space groups every element other than the identity has infinite order.
Fixed-point-free space groups in E2
Only two fixed-point-free space groups exist in E2: p1 and pg.
Fixed-point-free space groups in E3
Thirteen fixed-point-free space groups exist in E3: P1, P21, Pc, Cc, P212121, Pca21, Pna21, P41, P43, P31, P32, P61, P65.
See also
- Crystallographic orbit
- Point configuration
- Wyckoff position
- Chapter 1.4.4.2 of International Tables for Crystallography, Volume A, 6th edition