# Difference between revisions of "H centred cell"

### From Online Dictionary of Crystallography

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*[[Centred lattices]] | *[[Centred lattices]] | ||

*[[D centred cell]] | *[[D centred cell]] | ||

− | *Section | + | *Section 1.5 in the ''International Tables for Crystallography'', Volume A, 6<sup>th</sup> edition |

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

## Revision as of 15:49, 10 April 2017

Maille centrée H (*Fr*); Cella centrata H (*It*); H 複合単位胞 (*Ja*).

The **H centred cell** (**triple hexagonal cell**) is an alternative description of the hexagonal Bravais lattice. From the conventional *hP* cell one obtains the *hH* cell by taking the new basis vectors by means of one of the following transformation matrices, which give three possible orientations of the *hH* cell with respect to the *hP* cell:

*H*_{1}: 110/-120/001 *H*_{2}: 2-10/110/001 *H*_{3}: 1-20/2-10/001

The resulting *hH* cell has centring nodes at 1/3,2/3,0 and 2/3,1/3,0.

Secondary and tertiary elements in the *hP* cell are exchanged in the *hH* cell. For example, the space-group symbol *P*3*m*1 become *H*31*m* when the triple cell is used.

## See also

- Centred lattices
- D centred cell
- Section 1.5 in the
*International Tables for Crystallography*, Volume A, 6^{th}edition