The symmetry database provides access to the data from International Tables for Crystallography Volumes A and A1 and allows simple calculations using the data to be performed. These calculations include generator and general-position transformations, Wyckoff-position transformations and some group-subgroup pair calculations such as coset decomposition and Wyckoff-position splittings.
SymbolsThe following symbols are used in the symmetry database:
|The info symbol indicates that there is a help page providing more information about the data presented on the current page. Click on the symbol to see this information.|
|Click on the slide down symbol to see some additional information related to the current page.|
|Click on the slide up symbol to hide the additional information shown after you have clicked on the slide down symbol.|
|This symbol is shown to indicate that a calculation is in process. If you see this symbol, please wait until the calculation is finished and the result is shown.|
The conventions used for the default settings of the space groups are:
- for monoclinic groups: unique axis b, cell choice 1;
- for orthorhombic groups: the 'standard setting' as defined in Section 188.8.131.52.4 of Volume A (or Section 2.2.6 in the first online edition of Volume A);
- for space groups with two origin choices: origin choice 2;
- for trigonal space groups: hexagonal axes.
For space groups with more than one conventional setting, abutton is provided:
When you click on this button, a list of the conventional settings is shown. When you select a specific setting, the corresponding data for the selected setting are shown.
On the pages that show data that can be transformed to a non-conventional basis, abutton is provided:
Clicking on the button opens a form in which the axes transformation and the origin shift can be entered:
The origin-shift coordinates can be specified with real numbers or fractions: e.g. 0.5 or 1/2.
Once the transformation information has been entered, click on thebutton to see the transformed group data.