The Elusive Structural Origin of Plastic Bending in Dimethyl Sulfone Crystals with Quasi-isotropic Crystal Packing

Bending in molecular crystals is typically associated with the anisotropy of intermolecular interactions. The intriguing observation is reported of plastic bending in dimethyl sulfone, which exhibits nearly isotropic crystal packing and interaction topology, defying the known structural models of bending crystals. The origin of the bending phenomenon has been explored in terms of intermolecular interaction energies, experimental X-ray charge density analysis, and variable temperature neutron diffraction studies. H center dot center dot center dot H dihydrogen interactions and differences in electrostatic complementarity between molecular layers are found to facilitate the bending behavior.