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Figure 3
An illustration of Criterion 3[link] using simulated CBED patterns of alpha-quartz near [[\bar 1 \bar 3 \bar 7]]. Two different types of alpha-quartz which belong to different space groups are used: the structure in (a) and (b) is in the space group P3221, the structure in (c) and (d) is in the space group P3121. The two structures are enantiomorphs of each other. The yellow circles enclose the three-beam conditions and their neighourhoods. For the structure in (a) and (b), [\phi = {\varphi _{\overline 2,3,\overline 1}} - {\varphi _{1,2,\overline 1}} + {\varphi _{3,\overline 1,0}}] = 103°. For the structure in (c) and (d), [\phi = {\varphi _{\overline 2,3,\overline 1}} - {\varphi _{1,2,\overline 1}} + {\varphi _{3,\overline 1,0}}] = −103°.

IUCrJ
Volume 5| Part 6| November 2018| Pages 753-764
ISSN: 2052-2525
https://doi.org/10.1107/S2052252518012216