International
Tables for Crystallography Volume B Reciprocal space Edited by U. Shmueli © International Union of Crystallography 2010 
International Tables for Crystallography (2010). Vol. B, ch. 2.5, p. 346
Figure 2.5.3.16
M. Tanaka^{f}


Figure 2.5.3.16
CBED patterns of Sm_{3}Se_{4}. The procedures for identifying the symmetry are also shown. (a, b) [111] incidence at 80 kV: the WP symmetry is 3m (a) and the projection (proj.) WP symmetry is 3m (b). (c, d) [100] incidence at 80 kV: the WP symmetry is 2mm (c) and the projection WP symmetry is 4mm (d). Dynamical extinction lines A_{2} and A_{3} are seen (d). The point group is determined to be . (e) Spot diffraction pattern taken with the [100] incidence at 80 kV shows the absence of 0kl reflections. The lattice type is determined to be I. (f) [100] incidence at 100 kV: dynamical extinction lines A in HOLZ reflections confirm the existence of a glide plane. The space group is determined to be . 