Actions

Difference between revisions of "Ogdohedry"

From Online Dictionary of Crystallography

m (Definition: link)
(+ cat)
Line 13: Line 13:
  
  
[[Category:Fundamental crystallography]]
+
[[Category:Fundamental crystallography]]<br>
 +
[[Category:Morphological crystallography]]

Revision as of 04:59, 3 December 2014

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