Acta Crystallographica Section C
The molecular structures of 4,7-dichlorobenzo[c]furazan 1-oxide, C6H2Cl2N2O2, (I), and 4,7-dibromobenzo[c]furazan 1-oxide, C6H2Br2N2O2, (II), are normal. Compound (I) occurs in two polymorphic forms. One polymorph contains one molecule in the asymmetric unit, organized into two-dimensional sheets involving intermolecular N...Cl and O...Cl interactions. The second polymorph has three molecules in the asymmetric unit, organized into two crystallographically different two-dimensional sheets with similar interactions. Compound (II) is isomorphous with the second polymorph of (I). The three two-dimensional sheets in the two polymorphs comprise a set of three two-dimensional polymorphic arrangements.
The publisher's version can be found at http://journals.iucr.org/c/issues/2002/04/00/bk1639/index.html.
D. Britton, F. B. Mallory and C. W. Mallory (2002). Acta Cryst. C58, o235-o238.