1.39: D centered cell
The D centered cell is the used for the rhombohedral description of the hexagonal lattice. Six right-handed D cell with basis vectors of equal length are obtained from the hP cell by means of one of the following transformation matrices:
D 1 : 10-1/01-1/111 D 2 : -101/0-11/111
the other four D cells are obtained by cyclic permutation of the basis vectors.
The resulting hD cell has centering nodes at 1/3,1/3,1/3 and 2/3,2/3,2/3