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Figure 9
The charge density in a stack of equidistant tetra­chloro­semiquionone radical anions from the salt with the N-methyl­pyridinium cation (orthorhombic polymorph; a pair of contiguous radicals is shown; Molčanov et al., 2019BB53). (a) The experimentally determined electrostatic potential mapped onto an electron-density isosurface of 0.5 e Å−3 (red: −0.1, blue: 1.0 e Å−1). (b) The topology of the experimental electron density. Bonding critical points (3,−1) are depicted as red dots, ring critical points (3,+1) as light blue and cage critical points (3,+3) as violet. (c) The HOMOs calculated by DFT (B3LYP and M06-2X functionals with the def2-QZVPP basis set).

IUCrJ
Volume 6| Part 2| March 2019| Pages 156-166
ISSN: 2052-2525
https://doi.org/10.1107/S2052252519000186