Dimorphic forms in a non-centrosymmetric environment from a prochiral molecule: Cooperative interplay of strong hydrogen bonds and weak intermolecular interactions

4-Fluoro-N-(2-fluorophenyl) benzamide, a prochiral molecule, exhibits dimorphic behavior. This feature has been analyzed in terms of morphology, X-ray single-crystal structure analysis, differential thermal analysis, and measurement of second harmonic generation (SHG) in both forms, which crystallize in noncentric space groups. The dimorphs have different morphologies, a major form as needles and a minor form as thin plates, occurring concomitantly in the same crystallization setup. The plates crystallize in the monoclinic space group P2(1), while the needles are in the orthorhombic space group Pca2(1). Strong N-(HO)-O-... hydrogen bonds and weak but highly directional C-(HF)-F-... interactions acting cooperatively are responsible for the observed symmetry steering the molecules to pack in noncentric environments.