International
Tables for Crystallography Volume A Space-group symmetry Edited by Th. Hahn © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. A. ch. 1.4, pp. 7-11
https://doi.org/10.1107/97809553602060000503 Chapter 1.4. Graphical symbols for symmetry elements in one, two and three dimensions
a
Institut für Kristallographie, Rheinisch-Westfälische Technische Hochschule, Aachen, Germany This chapter lists the graphical symbols for symmetry elements used throughout this volume. The lists are accompanied by notes and cross-references to recent IUCr nomenclature reports. Keywords: symbols; crystallography; symmetry elements; symmetry planes; symmetry lines; symmetry axes. |
1.4.1. Symmetry planes normal to the plane of projection (three dimensions) and symmetry lines in the plane of the figure (two dimensions)
†
For further explanations of the `double' glide plane e see Note (iv)
![]() ![]() ![]() ‡Glide planes d occur only in orthorhombic F space groups, in tetragonal I space groups, and in cubic I and F space groups. They always occur in pairs with alternating glide vectors, for instance |
†
The symbols are given at the upper left corner of the space-group diagrams. A fraction h attached to a symbol indicates two symmetry planes with `heights' h and
![]() ‡For further explanations of the `double' glide plane e see Note (iv) ![]() ![]() ![]() §Glide planes d occur only in orthorhombic F space groups, in tetragonal I space groups, and in cubic I and F space groups. They always occur in pairs with alternating glide vectors, for instance |
1.4.3. Symmetry planes inclined to the plane of projection (in cubic space groups of classes
and
only)
†
The symbols represent orthographic projections. In the cubic space-group diagrams, complete orthographic projections of the symmetry elements around high-symmetry points, such as
‡For further explanations of the `double' glide plane e see Note (iv) ![]() ![]() ![]() §In the space groups ¶The glide vector is half of a centring vector, i.e. one quarter of the diagonal of the conventional body-centred cell in space groups ††Glide planes d occur only in orthorhombic F space groups, in tetragonal I space groups, and in cubic I and F space groups. They always occur in pairs with alternating glide vectors, for instance |
1.4.5. Symmetry axes normal to the plane of projection and symmetry points in the plane of the figure
†
Notes on the `heights' h of symmetry points |
†
The symbols for horizontal symmetry axes are given outside the unit cell of the space-group diagrams. Twofold axes always occur in pairs, at `heights' h and
|
†
The dots mark the intersection points of axes with the plane at
|
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