View source for H centred cell

<font color="blue">Maille centrée H</font> (''Fr''). <font color="black">Cella centrata H</font> (''It''). <font color="purple">H 複合単位胞</font> (''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''<sub>1</sub>: 110/-120/001 ''H''<sub>2</sub>: 2-10/110/001 ''H''<sub>3</sub>: 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]]
*Chapter 1.5 of ''International Tables for Crystallography, Volume A'', 6th edition

[[Category:Fundamental crystallography]]