Ques. on high symm points of a crystal

[sam_bell]

Hi! I'm new to these forums.

To get right to it, My head'z been spinning wondering ..

Is there a high symmetry point in a crystal about which *all* point operations can be re-centered? I can show this for a simple lattice.

Does anyone know if this is true for any complex crystal as well? And maybe how to show it? I'm asking because I want to write a program that sets the origin of coordinates at such a point and then tests all 48 possible operations about it. I know some good candidates would be at the atom centers and the midpoint between atoms.

Any knowledge/suggestions is appreciated. Thanks.

 

[johng23]

No, that's not possible. Think about the diamond structure for example. The center of symmetry is at 1/8 1/8 1/8, so this would be your only option for such a point. But the crystal has a diad perpendicular to each cube face, which cannot be placed so that it runs through the center of symmetry.

I can't give a more general answer unfortunately.