1.64: Laue classes
The Laue classes correspond to the eleven centrosymmetric crystallographic point groups. When absorption is negligible and Friedel's law applies, it is impossible to distinguish by diffraction between a centrosymmetric point group and one of its non-centrosymmetric subgroups.
| Laue classes |
Non-centrosymmetric groups
having the same Laue class |
| \({\bar 1}\) | 1 |
| 2/ m | 2, m |
| mmm | 222, 2 mm |
| \({\bar 3}\) | 3 |
| \({\bar 3}m\) | 32, 3 m |
| 4/ m | 4, \({\bar 4}\) |
| 4/ mmm | 422, \({\bar 4}2m\), 42 m |
| 6/ m | 6, \({\bar 6}\) |
| 6/ mmm | 622, \({\bar 6}2m\), 62 m |
| \(m{\bar 3}\) | 23 |
| \(m{\bar 3}m\) | 432, \({\bar 4}\)32 |