We give background information and (hopefully eventually) pages containing a definition and discussion of each of the 32 crystallographic discrete groups extending Paul Yale's crystallographic point groups on pages 107 -- 108 of his Geometry and Symmetry book. We use his notation for the groups rather than the standard names.

The general information is in GSChapter6 (PDF}

The code used (in PDF form for reading only) is in current code Crystallography (PDF)

The groups are

C1 Translations only C1 (PDF)

C2 Translation and a Half Turn C2 (PDF)

C3 Translations and order 3 rotation C3 (PDF)

C4 Translations and order 4 rotation C4 (PDF)

C6 Translations and order 6 rotation C6 (PDF)

More will be added as available.