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Updated: Jul 18, 2026

High Pressure Single Crystal Diffraction at PX^2
Published on: January 16, 2017
Order-disorder transition in monoclinic sulfur: a precise structural study by high-resolution neutron powder
W I F David1, R M Ibberson, S F J Cox
1ISIS Facility, CCLRC, Rutherford Appleton Laboratory, Chilton, Didcot, Oxfordshire OX11 0QX, England.
Abstract:
High-resolution neutron powder diffraction has been used in order to characterize the order-disorder transition in monoclinic cyclo-octasulphur. Rapid data collection and the novel use of geometrically constrained refinements has enabled a direct and precise determination of the order parameter, based on molecular site occupancies, to be made. The transition is critical and continuous; with a transition temperature, Tc=198.4 (3) K, and a critical exponent, beta=0.28 (3), which is indicative of three-dimensional ordering. Difficulties encountered as a consequence of the low thermal conductivity of the sample are discussed.
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