The symmetry of crystals. Representation
of crystal
classes
The
amount of combinations of symmetry elements (point groups) passing
through the center of a finite body can be very high. However in
crystals, which inherently contain repetitions by translation, the
amount of combinations of symmetry elements is restricted to 32, called
"crystal classes"… (see also this link).
Figures below show the representations of the 32 crystal classes as
shown
in the International
Tables for X-ray Crystallography:
Crystal classes
(The
centrosymmetric classes are marked with the word Laue)
Stereograms of poles of the 32 Crystal
Classes (first part) as they
appear in
International
Tables for X-ray Crystallography
(note that crystal class 2/m
appears in two different orientations)
(z-axis is always normal to the drawing
plane)
Stereograms of poles of the 32 Crystal
Classes (second part) as they
appear in
International
Tables for X-ray Crystallography
(z-axis is always normal to the drawing
plane)
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