crystal class


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crystal class

[′krist·əl ′klas]
(crystallography)
One of 32 categories of crystals according to the inversions, rotations about an axis, reflections, and combinations of these which leaves the crystal invariant. Also known as symmetry class.
References in periodicals archive ?
1 Crystal class 4-bar 3 m; (a) crystallographic symmetries and (b) elasto-piezo-dielectric matrix.
CRYSTAL CLASS: Marco Reich congratulates Andy Johnson after he put Palace ahead' MORRISON salutes the Palace winner
CRYSTAL CLASS: <Palace striker Morrison is now a hot property; STRIKING OUT: Bobby Robson; HEAD MAN: Pierre van Hooijdonk
Loudon derived the Raman tensors for each of the 32 crystal classes (symmetry point groups).
The paper is organized as follows: in Section 2 we determine the electrooptic crystal classes that are suitable for measuring the path integral of the electric field.
An analysis of the electrooptic (i.e., non-centrosymmetric) crystal classes yields several classes that meet the conditions for a path integration of the field [22,23]; that is, only the field component parallel to the optical path in Figure 1 shall cause an electrooptic phase shift whereas transverse components shall leave the phase difference unaffected.
Note that symmetry properties of the piezoelectric effect in certain crystal classes can also be employed to measure the path integral of the electric field with an optical sensor [24, 25].
Crystallographic Principles covers the following: (1) Crystal Systems; (2) Crystal Classes, Point Group Symmetry, and Symmetry Notations; [There is no section 3)]; (4) Miller Indices and Zone Symbols; (5) Crystal Forms; (6) Space Groups; (7) Choice of Settings; and (8) Twinning and Epitaxy.