At 103 K, imidazole, C3H4N2, is monoclinic, space group P21/c, with 4 molecules/unit cell and has lattice parameters a = 7.569 (1), b = 5.366, c = 9.785 (2) .ANG., and .beta. = 119.08 (1).degree.. The neutron structure determination using 1095 reflections gave R(F2) = 0.026 and Rw (F2) = 0.041. The estimated standard deviations in bond lengths (0.001 .ANG. for C-C, C-N) and angles are smaller than in previous X-ray and neutron determinations of this structure. The improved precision was needed in connection with an X-ray study of the charge density of imidazole.
