# Difference between revisions of "Geometric crystal class"

### From Online Dictionary of Crystallography

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− | <font color="blue">Classe cristalline géométrique</font> (''Fr''); <font color="red">Geometrische Kristallklasse</font> (''Ge''); <font color="green">Clase cristallina geométrica</font> (''Sp''); <Font color="black"> Classe cristallina geometrica </Font>(''It''). <Font color="purple"> 幾何的結晶類</Font> (''Ja'') | + | <font color="blue">Classe cristalline géométrique</font> (''Fr''); <font color="red">Geometrische Kristallklasse</font> (''Ge''); <font color="green">Clase cristallina geométrica</font> (''Sp''); <Font color="black"> Classe cristallina geometrica </Font>(''It''). <Font color="purple">幾何的結晶類</Font> (''Ja'') |

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'''Geometric crystal classes''' (or simply 'crystal classes') classify the symmetry groups of the external shape of macroscopic crystals, namely according to the morphological symmetry. There are 10 two-dimensional geometric crystal classes and 32 three-dimensional geometric crystal classes, in one to one correspondence with the 10 and 32 types of point groups in ''E''<sup>2</sup> and ''E''<sup>3</sup>, respectively. | '''Geometric crystal classes''' (or simply 'crystal classes') classify the symmetry groups of the external shape of macroscopic crystals, namely according to the morphological symmetry. There are 10 two-dimensional geometric crystal classes and 32 three-dimensional geometric crystal classes, in one to one correspondence with the 10 and 32 types of point groups in ''E''<sup>2</sup> and ''E''<sup>3</sup>, respectively. | ||

+ | |||

+ | == Japanese nomenclature == | ||

+ | The Japanese term commonly used to indicate a crystal class is 晶族 which however, as pointed out by Matsumoto (1977), is not an appropriate translation in that the character 族 is more suitable to indicate a [[crystal family]]. According to this author, a better translation of crystal class is 結晶類, which is therefore adopted in this dictionary. | ||

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

*[[Arithmetic crystal class]] | *[[Arithmetic crystal class]] | ||

*Section 8.2.4 of ''International Tables for Crystallography, Volume A''<br> | *Section 8.2.4 of ''International Tables for Crystallography, Volume A''<br> | ||

+ | *Matsumoto, T. (1977). ''J. Miner. Soc. Japan'', '''13''', 247-289. | ||

[[Category:Fundamental crystallography]] | [[Category:Fundamental crystallography]] |

## Revision as of 20:29, 26 April 2016

Classe cristalline géométrique (*Fr*); Geometrische Kristallklasse (*Ge*); Clase cristallina geométrica (*Sp*); Classe cristallina geometrica (*It*). 幾何的結晶類 (*Ja*)

## Definition

**Geometric crystal classes** (or simply 'crystal classes') classify the symmetry groups of the external shape of macroscopic crystals, namely according to the morphological symmetry. There are 10 two-dimensional geometric crystal classes and 32 three-dimensional geometric crystal classes, in one to one correspondence with the 10 and 32 types of point groups in *E*^{2} and *E*^{3}, respectively.

## Japanese nomenclature

The Japanese term commonly used to indicate a crystal class is 晶族 which however, as pointed out by Matsumoto (1977), is not an appropriate translation in that the character 族 is more suitable to indicate a crystal family. According to this author, a better translation of crystal class is 結晶類, which is therefore adopted in this dictionary.

## See also

- Arithmetic crystal class
- Section 8.2.4 of
*International Tables for Crystallography, Volume A* - Matsumoto, T. (1977).
*J. Miner. Soc. Japan*,**13**, 247-289.