# Difference between revisions of "Twin law"

### From Online Dictionary of Crystallography

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

− | The ''twin law'' expresses the operation that generate a twin. It is indicated by the symbol of the twinning element of symmetry: <math> \bar 1</math>, [uvw] and (''hkl'') for the centre of symmetry, direction of the rotation axis and [[Miller indices]] of the mirror plane, in the order. Usually, instead of the single (''hkl'') plane, the symbol {''hkl''} is used to indicate all the planes equivalent for symmetry. | + | The ''twin law'' expresses the operation that generate a twin. It is indicated by the symbol of the twinning 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. Usually, instead of the single (''hkl'') plane, the symbol {''hkl''} is used to indicate all the planes 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:Fundamental crystallography]] | [[Category:Fundamental crystallography]] |

## Revision as of 09:42, 26 April 2006

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

# Twin law

The *twin law* expresses the operation that generate a twin. It is indicated by the symbol of the twinning 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. Usually, instead of the single (*hkl*) plane, the symbol {*hkl*} is used to indicate all the planes equivalent for symmetry.

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