The crystal structure and electron density of 3-[(p-nitrophenoxy)methyl]-3-chlorodiazirine have been analyzed using single crystal X-ray diffraction at 208 K with Mo K alpha radiation to a resolution of sin(theta(max))/lambda = 1.126 Angstrom(-1). A total of 10 440 measured reflections gave 7742 unique reflections with R(m) = 0.026. A multipole atomic density model was fitted to these reflections to give an R(F) = 0.0311. The deformation density of the phenyl portion of the compound is as expected. The dynamic deformation density of the diazirine ring, however, suggests that the bonding in the three-membered ring is a combination of the classical severely-strained cr bonding system with a significant contribution of a a donation from the N=N to an sp(2) carbon. This observation is placed in the context of similar proposals for the bonding in cyclopropanes.