Neutron powder diffraction from samples frozen with quartz wool: hexafluorobenzene

Freezing of liquid samples in a vanadium can filled with quartz wool is found to be a successful way of preparing samples for neutron powder diffraction. A fairly complicated molecular structure - hexafluorobenzene - was chosen for study and the results of a constrained refinement with the program EDINP show the data to be good. Measurements were taken on the PANDA machine at AERE, Harwell at a temperature of 83 K. The technique should have an advantage over that used at present for the case of plastic crystals where the crystallites are in continual change. (Auth.)