The crystal packing of 4,7-dichloro- and 4,7-dibromobenzo[c]furazan 1-oxide.

The molecular structures of 4,7-dichlorobenzo[c]furazan 1-oxide, C(6)H(2)Cl(2)N(2)O(2), (I), and 4,7-dibromobenzo[c]furazan 1-oxide, C(6)H(2)Br(2)N(2)O(2), (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.