International
Tables for
Crystallography
Volume A
Space-group symmetry
Edited by M. I. Aroyo

International Tables for Crystallography (2016). Vol. A, ch. 1.6, p. 129

Figure 1.6.6.1 

J. C. H. Spencec
[Figure 1.6.6.1]
Figure 1.6.6.1

Polarity determination by convergent-beam electron diffraction. A CBED pattern from ZnO with the beam normal to the c axis is shown. The intensity distribution along c does not have inversion symmetry, reflecting the noncentrocentrosymmetric nature of the structure. Reproduced with permission from Wang et al. (2003[link]). Copyright (2003) by The American Physical Society.