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Difference between revisions of "Crystal pattern"

From Online Dictionary of Crystallography

 
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<Font color="blue">Motif cristallin </Font>(''Fr''). <Font color="black">Motivo cristallino</Font>(''It''). <Font color="purple"> 結晶模様 </Font>(''Ja'')
 
<Font color="blue">Motif cristallin </Font>(''Fr''). <Font color="black">Motivo cristallino</Font>(''It''). <Font color="purple"> 結晶模様 </Font>(''Ja'')
  
A '''crystal pattern''' is the idalized image of a crystal structure obtained by neglecting all the defects of the crystal structure and making it infinitely periodic.
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An object in the n-dimensional [[point space]] E<sup>n</sup> is called an n-dimensional '''crystallographic pattern''' or, for short, '''crystal pattern''' if among its symmetry operations:
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# there are ''n'' translations, the translation vectors '''t'''<sub>1</sub>, ... , '''t'''<sub>n</sub> of which are linearly independent;
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# all translation vectors, except the zero vector '''0''', have a length of at least d > 0.
  
The importance of the concept of crystal pattern becomes immediately evident if one considers that the operations of a space group are symmetry operations of the crystal pattern and not - rigorously speaking - of the crystal structure.
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When the crystal pattern consists of atoms, it takes the name of '''crystal structure'''. The crystal pattern is thus the generalization of a crystal structure to any pattern, concrete of abstract, in any dimension, which obeys the conditions of periodicity and discreteness expressed above.
  
 
== See also ==
 
== See also ==
 
*[[Point space]]
 
*[[Point space]]
*''International Tables of Crystallography, Volume A1''
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*''International Tables of Crystallography, Volumes A and A1''
  
 
[[Category:Fundamental crystallography]]
 
[[Category:Fundamental crystallography]]

Revision as of 15:11, 8 May 2008

Motif cristallin (Fr). Motivo cristallino(It). 結晶模様 (Ja)

An object in the n-dimensional point space En is called an n-dimensional crystallographic pattern or, for short, crystal pattern if among its symmetry operations:

  1. there are n translations, the translation vectors t1, ... , tn of which are linearly independent;
  2. all translation vectors, except the zero vector 0, have a length of at least d > 0.

When the crystal pattern consists of atoms, it takes the name of crystal structure. The crystal pattern is thus the generalization of a crystal structure to any pattern, concrete of abstract, in any dimension, which obeys the conditions of periodicity and discreteness expressed above.

See also

  • Point space
  • International Tables of Crystallography, Volumes A and A1