# Difference between revisions of "Twin law"

### From Online Dictionary of Crystallography

Line 4: | Line 4: | ||

= Twin law = | = Twin law = | ||

− | The ''twin law'' expresses the operation that generates a ''[[twin]]''. It is indicated by the symbol of the | + | The ''twin law'' expresses the operation that generates a ''[[twin]]''. It is indicated by the symbol of the twin element of symmetry: <math> \bar 1</math>, [uvw] and (''hkl'') for the centre of symmetry (''[[inversion twin]]''), direction of the rotation axis (''[[rotation twin]]'') and [[Miller indices]] of the mirror plane (''[[reflection twin]]''), in the order. Except when one refers to a specific plane or direction, the symbols {''hkl''} or <''uvw''> must be used to indicate all the planes or directions which are equivalent for symmetry. |

Chapter 3.3 of ''International Tables of Crystallography, Volume D''<br> | Chapter 3.3 of ''International Tables of Crystallography, Volume D''<br> | ||

[[Category:Twinning]] | [[Category:Twinning]] |

## Revision as of 13:23, 23 May 2006

Loi de macle (*Fr*). Legge di geminazione (*It*)

# Twin law

The *twin law* expresses the operation that generates a *twin*. It is indicated by the symbol of the twin element of symmetry: [math] \bar 1[/math], [uvw] and (*hkl*) for the centre of symmetry (*inversion twin*), direction of the rotation axis (*rotation twin*) and Miller indices of the mirror plane (*reflection twin*), in the order. Except when one refers to a specific plane or direction, the symbols {*hkl*} or <*uvw*> must be used to indicate all the planes or directions which are equivalent for symmetry.

Chapter 3.3 of *International Tables of Crystallography, Volume D*