The influence of pressure and temperature on the crystal structure of acetone

Dipolar carbonyl–carbonyl contacts generally occur in one of three motifs, and all are exhibited in the X-ray crystal structures of two phases of acetone derived at 15 kBar and at 150 K; a neutron powder-diffraction study at 5 K and an X-ray diffraction study at 110 K reveal strengthened CH···O as well as CO···CO electrostatic contacts which appear to explain the unusual thermodynamic properties of acetone, the nature of which have remained a mystery since 1929.