Electron microscopy
 
Laue Class/Laue Symmetry
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The point group of a diffraction pattern is often called “Laue class” of the diffraction pattern. Table 3020 shows  the relationship between Laue classes and point groups.

Table 3020. Relationship between Laue classes and point groups.

System Essential symmetry  Lattice symmetry  Symmetry equivalent reflections * Laue class (Diffraction symmetry) Point Groups (Hermann–Mauguin notation)
Triclinic None Triclinic 2: hkl, -h-k-l Triclinic 1, -1
Monoclinic Monoclinic 2/m 4: hkl, -h-k-l, h-kl, h-kl 2/m 2, m, 2/m
Orthorhombic 222 or 2mm
mmm
8: hkl, -h-k-l, h-kl, h-kl, -hkl, hk-l, -h-kl, h-k-l mmm 222, mm2, mmm
Tetragonal Tetragonal 4/mmm
8: hkl, -h-k-k, khl, -k-h-l, hk-l, -h-kl, kh-l, -k-hl 4/m
4, -4, 4/m
16: 4/mmm 422, -42m, 4mm, 4/mmm
Trigonal Trigonal Trigonal 6: 3 3, -3
12: -3m1 321, 3m1, -3m1
12: -31m 312, 31m, -31m
Hexagonal Hexagonal 6/mmm
12: 6/m 6, -6, 6/m
24: 6/mmm 622, -62m, 6mm, 6/mmm
Cubic 23 m3m
24: m-3 23, m-3
48: m-3m 432, -43m, m-3m
* Symmetry equivalent reflections: All of them have the same intensity.

 

 

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