icosahedral_symmetry_matrices ( orientation='222' )

1. icosahedral symmetry matrices.

   Allowed orientations are:

   1. -> x 2-fold axis, y 2-fold, z 2-fold 222r -> x 2-fold axis, y 2-fold, z 2-fold 2n3 -> x 2-fold axis, z 3-fold 2n5 -> x 2-fold axis, z 5-fold