The structure of methanol at 5.09 GPa: the fortuitous formation of a new high-pressure phase

The crystal structure of a new polymorph of methanol (the polymorph) has been determined at 5.09 GPa by single crystal X-ray diffraction. The polymorph crystallises in the monoclinic space group, P 2 1 / c , with twelve molecules in the unit cell, and exhibits a 4-membered hydrogen bonded ring structure, never previously observed in any crystal structure of methanol. The phase was also serendipitously seeded by the presence of another crystallite, giving rise to suitable crystallisation conditions 2 GPa lower than previously reported. The crystal structure of a new polymorph of methanol (the polymorph) has been determined at 5.09 GPa by single crystal X-ray diffraction.