3-Chloro-N,N-dimethylpropan-1-aminium chloride

The organic cation in the title molecular salt, C5H13NCl+·Cl−, exhibits the gauche effect with a C—H bond of the C atom β to the chloro group donating electrons to the antibonding orbital of the C—Cl bond to stabilize the gauche conformation [Cl—C—C—C = −68.6 (6)°], as confirmed by DFT geometry optimizations that show a lengthening of the C—Cl bond relative to that of the anti conformation. Of further interest is the higher point group symmetry of the crystal (\overline{4}), compared that of the that of the molecular cation, which arises from a supramolecular head-to-tail square arrangement of four molecular cations that circulate in a counterclockwise direction when viewed down the tetragonal c axis.