Intermolecular π-π Stacking Interactions Made Visible.

Mixing the liquids hexafluorobenzene () and 1,3,5-trimethylbenzene (mesitylene, ) results in a crystalline solid with a melting point of 34 °C. The solid consists of alternating π-π stacked pillars of both aromatics. This simple experiment can be used to visually demonstrate the existence and the effect of noncovalent intermolecular π-π stacking interactions.