Layers having obvious approximate symmetry higher than that of the overall 3-D crystal are present in 20–25% of the Z ′ > 4 and P 1 organic structures archived in the Cambridge Structural Database. In some structures different types of layers alternate.
No takes yet. Share an insight, caveat, or question.
C.P. Brock (2020) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: