Crystal structure of chloroiodomethane

The crystal structure of phase III of chloroiodomethane-d 2 was determined at 13 K using Rietveld refinement of neutron powder profiles. The space group is Pnma (D16 2h) and there are four molecules in its orthorhombic unit cell with dimensions a = 6·383(4) Å, b = 6·706(1) Å and c = 8·867(4) Å. The molecules form a 'herringbone' pattern in layers perpendicular to the b axis, similar to that in the halogen and the hydrogen halides crystals.