International
Tables for Crystallography Volume D Physical properties of crystals Edited by A. Authier © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. D, ch. 1.1, pp. 18-19
Section 1.1.4.8.5. Tetragonal system^{a}Institut de Minéralogie et de la Physique des Milieux Condensés, Bâtiment 7, 140 rue de Lourmel, 75015 Paris, France |
The method of direct inspection can be applied for a fourfold axis. One finds
There are 7 independent components.
The matrix corresponding to axis is and the form of the matrix is
There are 6 independent components.
One combines either the reductions for groups and 222, or the reductions for groups and 2mm.
The number of independent components is of course the same, 6.