2. Content
•Introduction
•Transformation operators for the crystallographic symmetry elements
•2-D point groups
•3-D symmetry Operators
•3-D point groups
•Standard settings
•The fourteen Bravais Networks
•The forteen symmetry elements generate the 32 cristal clases
•Curie groups symmetries
•Bibliography
3. Introduction
Since the pysical property tensors depend on symmetry,
mathematical methods for determining the influence of
symmetry are needed.
More specifically, transformations matrices are required for
the symmetry elements that generate the cristal class.
4. Transformation operators for the
crystallographic symmetry elements
There are four types of
symmetry elements that require
discussion: rotation axes, mirror
planes, inversión centers, and
inversión axes in which rotation
is accompanied by inversión.
14. Curie group symmetries
In many practical applications engineers work with amorphous
or polycrystalline materials rather than single crystals.
Such materials are often processed in such a way that their
properties are anisotropic.
The symmetry of these textured materials can often be
described by curie group symmetries.
15. The Curie groups all have a
common symmetry element
represented by an ∞-fold
rotation axis. The
transformation matrix for ∞-
fold axis parallel to Z3 is
16. Polycrystalline metals and
ceramics with randomly oriented
grains possess spherical
symmetry ∞ ∞m.
Processed polycrystalline
materials may also adopt
crystallographics symmetry.
17. Liquids and liquid crystals
exhibit a number of
different Curie group
symmetries
18. When sugar is dissolved in water it induces optical
activity causing the plane of polarization of light to be
rotated.