Neutron powder and ab initio structure of ortho-xylene: The influence of crystal packing on phenyl ring geometry at 2 K

Crystal packing effects in the previously unknown structure of ortho- xylene are found to induce a high degree of strain to the phenyl ring which is not observed in high-level ab initio structure calculations or in the crystal structures of the para and meta isomers; the potential for aromatic hydrogen bonding in the structure is discussed.