Monoclinic Sulfur: Heat Capacity Anomaly at 198°K Caused by Disordering of the Crystal Structure

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Science  03 May 1974:
Vol. 184, Issue 4136, pp. 562-563
DOI: 10.1126/science.184.4136.562


The entropy of disorder of the idealized crystal structure of monoclinic sulfur at high temperatures is equal to the extra entropy change in the lambda-type (second order transformation type) heat capacity anomaly found at 198°K. The extrapolated entropy is zero at 0°K. The partially disordered crystal structure gradually becomes ordered as the temperature is lowered.