title: Two polymorphs of 1,8-dichloroanthracene.
abstract: A second, monoclinic, polymorph of the title compound, C(14)H(8)Cl(2), has been found. In addition to the structure of this monoclinic form, the structure of the previously described orthorhombic form [Desvergne, Chekpo & Bouas-Laurent (1978). J. Chem. Soc. Perkin Trans. 2, pp. 84-87; Benites, Maverick & Fronczek (1996). Acta Cryst. C52, 647-648] has been redetermined at low temperature and using modern methods. The low-temperature structure of the orthorhombic form is of significantly higher quality than the previously published structure and additional details can be derived. A comparison of the crystal packing of the two forms with a focus on weak intermolecular C-H···Cl interactions shows the monoclinic structure to have one such interaction linking the molecules into infinite ribbons, while two crystallographically independent C-H···Cl interactions give rise to an interesting infinite three-dimensional network in the orthorhombic crystal form.
authors: Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue 2-325, Cambridge, MA 02139-4307, USA. pmueller@mit.edu
authors: Peter
authors: P
authors: Müller
authors: Frank R
authors: FR
authors: Fronczek
authors: Stacey J
authors: SJ
authors: Smith
authors: Teresa
authors: T
authors: Mako
authors: Mindy
authors: M
authors: Levine