Difference between revisions of "Ogdohedry"
From Online Dictionary of Crystallography
(→Definition) |
|||
| Line 1: | Line 1: | ||
| − | <font color="blue">Ogdoédrie </font>(''Fr''). <Font color="green"> Ogdoedria </Font>(''Sp''). <Font color="black"> Ogdoedria </Font>(''It'') | + | <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