From Online Dictionary of Crystallography
Revision as of 10:25, 16 May 2017 by BrianMcMahon (Style edits to align with printed edition)
Ogdoédrie (Fr). Ogdoedria (Sp). Ogdoedria (It). 八面像 (Ja)
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).
- Chapter 3.2.1 of International Tables for Crystallography, Volume A, 6th edition