Two polymorphs of 1,8-dichloro­anthracene

Müller, P.; Fronczek, F.R.; Smith, S.J.; Mako, T.; Levine, M.

doi:10.1107/S0108270113001790

Figure 4
Various packing views of the orthorhombic structure. C—H⋯Cl interactions are drawn as dashed lines. (a) The zigzag ribbon extending along the a axis, generated by the hydrogen bonds of atom H4. The angle between neighboring molecules is 55.816 (14)°. (b) The zigzag chain extending along the c axis, generated by the hydrogen bonds of atom H7. The angle between neighboring molecules is 51.494 (13)°. (c) A packing plot in projection along the b axis, providing a view down the helices that are formed by a combination of the motifs shown in (a) and (b). (d) A side view of the helix, which is built using all four general positions of space group Pna2₁ for each full turn. (e) Schematics of the anatomy of the helix, showing two turns. The molecules are represented by oval shapes and only those atoms directly interacting with a neighboring molecule protrude from the oval. Each of the four molecules in every full turn of a given helix contributes to that helix in a different way: one molecule binds to its neighbors through atoms H4 and H7, a second one through atoms H4 and Cl1, a third through atoms H7 and Cl1, and the fourth only through atom Cl1. [Symmetry codes in the centers of the ovals in part (e): (i) −x + 1, −y + 1, z − $[{1\over 2}]$ ; (ii) −x + $[{1\over 2}]$ , y − $[{3\over 2}]$ , z − $[{1\over 2}]$ ; (iii) x − $[{1\over 2}]$ , −y − $[{1\over 2}]$ , z; (iv) x − $[{1\over 2}]$ , −y + $[{5\over 2}]$ , z; (v) −y + $[{1\over 2}]$ , y + $[{3\over 2}]$ , z − $[{1\over 2}]$ ; (vi) −x + 1, −y + 4, z − $[{1\over 2}]$ ; (vii) x, y + 3, z.]

STRUCTURAL
CHEMISTRY

ISSN: 2053-2296

Volume 69| Part 2| January 2013| Pages 199-203

doi:10.1107/S0108270113001790

Search term		doi		Advanced search
Author		volume	page