Difference between revisions of "Subperiodic group"
From Online Dictionary of Crystallography
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| − | A '''subperiodic group''' is a group | + | A '''subperiodic group''' is a group of [[Euclidean mapping]]s such that its translations form a lattice in a proper subspace of the space on which it acts. |
| + | <br> | ||
| + | A '''crystallographic subperiodic group''' in n-dimensional space is a subperiodic group for which the group of linear parts is a crystallographic [[point group]] of n-dimensional space. The crystallographic subperiodic groups in two and three-dimensional space are classified in: | ||
*'''frieze groups''': 7 two-dimensional groups with one-dimensional translations; | *'''frieze groups''': 7 two-dimensional groups with one-dimensional translations; | ||
Revision as of 12:59, 1 April 2009
Groupe sous-périodique (Fr); Gruppo subperiodico (It).
A subperiodic group is a group of Euclidean mappings such that its translations form a lattice in a proper subspace of the space on which it acts.
A crystallographic subperiodic group in n-dimensional space is a subperiodic group for which the group of linear parts is a crystallographic point group of n-dimensional space. The crystallographic subperiodic groups in two and three-dimensional space are classified in:
- frieze groups: 7 two-dimensional groups with one-dimensional translations;
- rod groups: 75 three-dimensional groups with one-dimensional translations;
- layer groups: 80 three-dimensional groups with two-dimensional translations.
See also
International Tables of Crystallography, Volume E