Crystal structure of 2-chloroacetamide (α form): A reinvestigation

The crystal structure of the form of 2-chloroacetamide, grown by sub-limation, has been determined from three-dimensional counter data and refined by full-matrix least-squares techniques. The crystals belong to the monoclinic space groupP2₁/c witha=10.263(8),b=5.142(5),c=7.458(6) Å, =98.72(4) °, andD _x=1.60 g cm^–3 forZ=4. The finalR factor for 518 observed reflections is 0.037. The molecule exists as a hydrogen-bonded dimer in the crystal structure. The configuration of atoms C(1), C(2), O, and N is planar to within 0.008 Å, and the Cl—C(1)—C(2)—O dihedralangle equals 168 °. The dimeric hydrogen bonding as well as the CH₂ conformation favors the stabilization of a transient oxygen-centered radical.