5-Iodo­benzofurazan 1-oxide: polymorphs, pseudosymmetry and disorder

Britton, D.; Noland, W. E.; Clark, C. M. Acta Cryst. Sect. C, 2008, 64, o187. 

5-Iodobenzofurazan 1-oxide (systematic name: 5-iodobenzo- 1,2,5-oxadiazole 1-oxide), C6H3IN2O2, occurs in two poly-morphic forms, both monoclinic inP21/cwithZ0=2.Theintermolecular interactions in the two polymorphs are quitedifferent. In polymorph (I), there are strong intermolecularI O interactions, with IO distances of 3.114 (8) and3.045 (8) A In polymorph (II), there are strong intermol- ecular I  N interactions, with I  N distances of 3.163 (4) and 3.175 (5) A ̊ . In (I), there is about 15% disorder in one molecule and about 5% in the other. In both polymorphs, there are pseudosymmetric relationships between the crystal- lographically independent molecules.