What is a Laue group?

The Laue group. describes the symmetry of the diffraction pattern. The Laue symmetry can. be lower than the metric symmetry of the unit cell, but never higher. That means: A monoclinic crystal with β = 90° is still monoclinic.

What crystal is hexagonal?

Among the primary crystal systems, the hexagonal system has the fewest substances assigned to it, including arsenic, calcite, dolomite, quartz, apatite, tourmaline, emerald, ruby, cinnabar, and graphite.

Which space groups have inversion symmetry?

The following space groups have inversion symmetry: the triclinic space group 2, the monoclinic 10-15, the orthorhombic 47-74, the tetragonal 83-88 and 123-142, the trigonal 147, 148 and 162-167, the hexagonal 175, 176 and 191-194, the cubic 200-206 and 221-230.

How many times does rotation occur in a Laue group?

The Laue groups have always exactly twice as many symmetry elements as the corresponding enantiomorphic group. As the following example illustrates each symmetry element from the enantiomorphic group occurs two times – with and without inversion – in the corresponding Laue group. cs = crystalSymmetry(‘222’); rotation(cs) rotation(cs.Laue)

Can a Laue group be derived from an enantiomorphic group?

Since all Laue groups can be derived from the 11 enantiomorphic groups there are also 11 Laue groups, namely -1, 2/m, mmm, -3, -3m, -4/m, 4/mmm, 6/m, 6/mmm, m-3, m-3m. The Laue groups have always exactly twice as many symmetry elements as the corresponding enantiomorphic group.

How many Laue groups are there in the world?

There are 11 Laue groups: -1, 2/m, mmm, 4/m, 4/mmm, -3, -3/m, 6/m, 6/mmm, m3, m3m Laue Symmetry

Can a Laue group be defined by a command?

More directly, the Laue group corresponding to an arbitrary point group can be defined by the command Since all Laue groups can be derived from the 11 enantiomorphic groups there are also 11 Laue groups, namely -1, 2/m, mmm, -3, -3m, -4/m, 4/mmm, 6/m, 6/mmm, m-3, m-3m.