The ab initio crystal structure determination of vapour-deposited methyl fluoride by high-resolution neutron powder diffraction

The crystal structure of methyl fluoride (m.p. = 131 K, b.p. = 195 K) at 5 K has been solved ab initio from high-resolution neutron powder diffraction data. A good quality powder sample was produced using a vapour deposition technique and enabled an accurate and precise structure refinement to be carried out; the C—F bond length is 1.399 (4) Å, and the average C—D bond length is 1.070 (4) Å. The monoclinic structure may be described in terms of dipole-dipole intermolecular interactions and is distinct from the structures of the other methyl halides.