Practical Hints and Tips for Solution of Pseudo-Merohedric Twins: Three Case Studies

Authors

Sean R. Parkin, University of KentuckyFollow

Abstract

Twinning by pseudo-merohedry is a common phenomenon in small-mol­ecule crystallography. In cases where twin-component volume fractions are markedly different, structure solution is often no more difficult than for non-twinned structures of similar complexity. When twin-component volume fractions are similar, however, structure solution can be much more of a problem. This paper presents hints and tips for such cases by means of three worked examples. The first example presents the most common (and simplest) case of a two-component pseudo-ortho­rhom­bic twin. The second example describes structure solution of a reticular threefold pseudo-hexa­gonal twin that benefits from use of an unconventional space-group setting. The third example covers structure solution of a reticular fourfold pseudo-tetra­gonal twin. All three structures are ultimately shown to be monoclinic crystals that twin as a consequence of unit-cell metrics that mimic those of higher symmetry crystal systems.

Document Type

Article

Publication Date

4-9-2021

Notes/Citation Information

Published in Acta Crystallographica Section E, v. 77, part 5.

This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.

Digital Object Identifier (DOI)

https://doi.org/10.1107/S205698902100342X

Repository Citation

Parkin, Sean R., "Practical Hints and Tips for Solution of Pseudo-Merohedric Twins: Three Case Studies" (2021). Chemistry Faculty Publications. 179.
https://uknowledge.uky.edu/chemistry_facpub/179