Crystal structure and Hirshfeld surface analysis of 4-(2-chloro-eth-yl)-5-methyl-1,2-di-hydro-pyrazol-3-one.

In the crystal of the title compound, C 6 H 9 ClN 2 O, mol-ecular pairs form dimers with an R 2 2 (8) motif through N-H⋯O hydrogen bonds. These dimers are connect into ribbons parallel to the (100) plane with R 4 4 (10) motifs by N-H⋯O hydrogen bonds along the c- axis direction. In addition, π-π [centroid-to-centroid distance = 3.4635 (9) Å] and C-Cl⋯π inter-actions between the ribbons form layers parallel to the (100) plane. The three-dimensional consolidation of the crystal structure is also ensured by Cl⋯H and Cl⋯Cl inter-actions between these layers. According to a Hirshfeld surface study, H⋯H (43.3%), Cl⋯H/H⋯Cl (22.1%) and O⋯H/H⋯O (18.7%) inter-actions are the most significant contributors to the crystal packing.