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Difference between revisions of "Ogdohedry"

From Online Dictionary of Crystallography

(Definition)
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<font color="blue">Ogdoédrie </font>(''Fr''). <Font color="green"> Ogdoedria </Font>(''Sp''). <Font color="black"> Ogdoedria </Font>(''It'')
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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'')
  
  

Revision as of 18:53, 2 March 2007

Ogdoédrie (Fr). Ogdoedria (Sp). Ogdoedria (It). 八面像 (Ja)


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 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).

See also

Section 9.1 of International Tables of Crystallography, Volume A