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Difference between revisions of "Ogdohedry"

From Online Dictionary of Crystallography

(Added German translation (U. Mueller))
 
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<font color="blue">Ogdoédrie </font>(''Fr''). <Font color="green"> Ogdoedria </Font>(''Sp''). <Font color="black"> Ogdoedria </Font>(''It''). <Font color="purple"> 八面像 </Font>(''Ja'')
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<font color="blue">Ogdoédrie</font> (''Fr''). <font color="red">Ogdoedrie</font> (''Ge''). <font color="black">Ogdoedria</font> (''It''). <font color="purple">八面像</font>(''Ja''). <font color="green">Ogdoedría</font> (''Sp'').
  
  
 
== Definition ==
 
== Definition ==
  
The point group of a crystal is called ogdohedry if it is a subgroup of index 8 of the point group of its lattice.
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The [[point group]] of a crystal is called ogdohedry if it is a subgroup of index 8 of the point group of its lattice.
  
In the three dimensional space there is only one ogdohedry: it corresponds to the [[geometric crystal class]] 3 of crystals belonging to the hexagonal [[lattice system]] (in case rhombohedral crystals, it corresponds instead to a [[tetartohedry]]).
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In three-dimensional space there is only one ogdohedry: it corresponds to the [[geometric crystal class]] 3 of crystals belonging to the hexagonal [[lattice system]] (in the case of rhombohedral crystals, it corresponds instead to a [[tetartohedry]]).
  
 
== See also ==
 
== See also ==
 
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*[[Merohedry]]
Section 9.1 of ''International Tables of Crystallography, Volume A''
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*[[Tetartohedry]]
 
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*Chapter 3.2.1 of ''International Tables for Crystallography, Volume A'', 6th edition
  
 
[[Category:Fundamental crystallography]]
 
[[Category:Fundamental crystallography]]
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[[Category:Morphological crystallography]]

Latest revision as of 13:17, 16 November 2017

Ogdoédrie (Fr). Ogdoedrie (Ge). Ogdoedria (It). 八面像(Ja). Ogdoedría (Sp).


Definition

The point group of a crystal is called ogdohedry if it is a subgroup of index 8 of the point group of its lattice.

In three-dimensional space there is only one ogdohedry: it corresponds to the geometric crystal class 3 of crystals belonging to the hexagonal lattice system (in the case of rhombohedral crystals, it corresponds instead to a tetartohedry).

See also