An orthorhombic polymorph of 10,11-dihydrocarbamazepine.

The title compound (systematic name: 10,11-dihydro-5H-dibenz[b,f]azepine-5-carboxamide), C15H14N2O, is shown to crystallize as an orthorhombic polymorph to complement the known monoclinic form. The molecular conformations of both forms are very similar, involving a bent conformation for the seven-membered azepine ring and an overall ;butterfly' shape. The molecules assemble into chains by way of N-H...O bonds and N-H...pi interactions in both crystal modifications. The two polymorphs appear to form due to different van der Waals interactions between the layer-like sheets of molecules.