International
Tables for
Crystallography
Volume E
Subperiodic groups
Edited by V. Kopský and D. B. Litvin

International Tables for Crystallography (2010). Vol. E, ch. 1.2, p. 7   | 1 | 2 |

Section 1.2.2. Contents and arrangement of the tables

V. Kopskýa and D. B. Litvinb*

aFreelance research scientist, Bajkalská 1170/28, 100 00 Prague 10, Czech Republic, and bDepartment of Physics, The Eberly College of Science, Penn State – Berks Campus, The Pennsylvania State University, PO Box 7009, Reading, PA 19610–6009, USA
Correspondence e-mail:  u3c@psu.edu

1.2.2. Contents and arrangement of the tables

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The presentation of the subperiodic group tables in Parts 2[link] , 3[link] and 4[link] follows the form and content of IT A (2005[link]). The entries for a subperiodic group are printed on two facing pages or continuously on a single page, where space permits, in the following order (deviations from this standard format are indicated on the relevant pages):

  • Left-hand page:

  • (1) Headline;

  • (2) Diagrams for the symmetry elements and the general position;

  • (3) Origin;

  • (4) Asymmetric unit;

  • (5) Symmetry operations.

  • Right-hand page:

  • (6) Headline in abbreviated form;

  • (7) Generators selected: this information is the basis for the order of the entries under Symmetry operations and Positions;

  • (8) General and special Positions, with the following columns: Multiplicity; Wyckoff letter; Site symmetry, given by the oriented site-symmetry symbol; Coordinates; Reflection conditions;

  • (9) Symmetry of special projections;

  • (10) Maximal non-isotypic non-enantiomorphic subgroups;

  • (11) Maximal isotypic subgroups and enantiomorphic sub­groups of lowest index;

  • (12) Minimal non-isotypic non-enantiomorphic supergroups.

1.2.2.1. Subperiodic groups with more than one description

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For two monoclinic/oblique layer-group types with a glide plane, more than one description is available: p11a (L5) and p112/a (L7). The synoptic descriptions consist of abbreviated treatments for three `cell choices', called `cell choices 1, 2 and 3' [see Section 1.2.6[link], (i) Layer groups[link]]. A complete description is given for cell choice 1 and it is repeated among the synoptic descriptions of cell choices 2 and 3. For three layer groups, p4/n (L52), p4/nbm (L62) and p4/nmm (L64), two descriptions are given (see Section 1.2.7[link]). These two descriptions correspond to the choice of origin, at an inversion centre and on a fourfold axis. For 15 rod-group types, two descriptions are given, corresponding to two settings [see Section 1.2.6[link], (ii) Rod groups[link]].

References

International Tables for Crystallography (2005). Vol. A, Space-Group Symmetry, edited by Th. Hahn. Heidelberg: Springer. [Previous editions: 1983, 1987, 1992, 1995 and 2002. Abbreviated as IT A (2005).]








































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