R. Myers, B. H. Torrie, B. M. Powell
1983
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0
Influential Citations
22
Citations
Journal
Journal of Chemical Physics
Abstract
The crystal structures of the three solid phases of deuterated bromoform have been determined using the neutron powder profile refinement technique. At 273 K, there are two molecules per unit cell in a hexagonal structure with space group P3. The molecules are statistically disordered to give a pseudosymmetry with space group P63/m. Rapid cooling of the sample freezes out the dynamic disorder and results in a metastable structure with trigonal space group P3, in which a given molecule is surrounded by molecules of the opposite orientation with C–D bonds in the c direction. This structure can be viewed as being made up of molecular bilayers parallel to the basal plane with the deuterium atoms in the interior of a bilayer. The transformation from this metastable trigonal phase to the stable phase at low temperatures involves mainly a translational motion of one bilayer with respect to the neighboring bilayers. Assuming threefold molecular symmetry, this structure has been determined at 14 and 220 K. It is...