Fig. 1: Statistical distributions for all \({Z}^{{\prime} }\le 5\) structures in the Cambridge Structural Database (CSD) composed of C, H and O atoms.
From: Rapid prediction of molecular crystal structures using simple topological and physical descriptors
a Distributions of the minimum angle formed by the vectors ei and nc for \({n}_{\max }=5\). The 95% and 99% confidence intervals are within 3 degrees, suggesting a restriction in the orientation of the inertial eigenvectors related to the vector set nc. b Distributions of the minimum angle formed by the vectors kr, defined to be perpendicular to the average plane of the benzene rings, and nc for \({n}_{\max }=5\). c The van der Waals (vdW) free volume as a fraction of the unit cell volume. d The molecular van der Waals volume (vdW)mol as a fraction of the unit cell volume Ω for crystals with four molecules in the unit cell (Z = 4). e, f Distributions of the lengths of the C–H and O–H close contacts for contact length l ≤ (sum of vdW radii + 0.5)Å. The close contacts are characterized as line-of-sight contacts, for which the position vector connecting the two atoms does not intersect the vdW sphere of a third atom. The peak of the distribution for the line-of-sight contacts provide the optimal separation between the two atoms forming the contact. The distribution for the C–H contacts is characteristic of all contacts involving at least one C atom while the O–H distribution is characteristic of the contacts between a hydrogen and a highly electronegative atom. The presence of intermolecular hydrogen bonding creates a secondary peak characteristic of the optimal hydrogen bond length affecting the connectivity of neighboring molecules in the unit cell. Source data are provided as a Source Data file.
