Dichloromaleic anhydride

Abstract

Although molecules of the title compound, 3,4-dichloro-2,5-dihydrofuran-2,5-dione (dichloromaleic anhydride, C(4)Cl(2)O(3)), (I), possess approximate non-crystallographic C(2v) symmetry, the two chlorine substituents deviate from the ring plane. Their deviations are in the same direction, but with values of 0.0356 (17) and 0.0167 (17) A, they differ significantly in magnitude. The closest intermolecular contact is of 2.888 (2) A between a carbonyl O atom and the C atom of a carbonyl group, with the O.C direction orthogonal to the C=O bond [O5.C2(i)=O2(i) 93.6 (2) degrees; symmetry code: (i) $3 \over 2$ - x, -(1/2) + y, z]. These contacts form infinite chains of molecules running parallel to the crystallographic b direction.