Editing Crystal structure (section)

=== Space groups ===
In addition to the operations of the point group, the [[space group]] of the crystal structure contains translational symmetry operations. These include:
*Pure ''translations'', which move a point along a vector
*''Screw axes'', which rotate a point around an axis while translating parallel to the axis.<ref name=Sands>
{{cite book |title=Introduction to Crystallography |author=Donald E. Sands |chapter-url=https://books.google.com/books?id=h_A5u5sczJoC&pg=PA71 |chapter=§4-2 Screw axes and §4-3 Glide planes |pages= 70–71 |isbn=978-0486678399 |publisher=Courier-Dover |year=1994 |edition=Reprint of WA Benjamin corrected 1975}} 
</ref>
*''Glide planes'', which reflect a point through a plane while translating it parallel to the plane.<ref name=Sands/>

There are 230 distinct space groups.