# Difference between revisions of "Ogdohedry"

### From Online Dictionary of Crystallography

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== See also == | == See also == | ||

− | + | *Section 3.2.1 of ''International Tables of Crystallography, Volume A'', 6<sup>th</sup> edition | |

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[[Category:Fundamental crystallography]]<br> | [[Category:Fundamental crystallography]]<br> | ||

[[Category:Morphological crystallography]] | [[Category:Morphological crystallography]] |

## Revision as of 16:21, 10 April 2017

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 3.2.1 of
*International Tables of Crystallography, Volume A*, 6^{th}edition