The organic molecule below,
. There is only one symmetry
element in this space group - a center of symmetry at the origin of the unit cell. The center of symmetry
“inverts” each atom through the origin to produce an identical symmetry-related atom with co-ordinates
-x, -y, -z (click on “center”).
Due to the nature of unit cells, if there is a center of symmetry at (0, 0, 0), there is also one at (½, ½, ½). This molecule can be moved into the unit cell by translating it one unit cell length in each cell direction (click on “translate 1 1 1”):
The two molecules displayed in the unit cell are related by a center of symmetry at ½, ½, ½.
