LOW-TEMPERATURE HEAT-CAPACITY OF CELESTIT E SRSO4

The low-temperature heat capacity of celestite SrSO4 within the range from 9.49 to 302.96K was measured by the adiabatic calorimetry techniq ue. The standard heat capacity, entropy, and change of enthalpy at 298 .15K have the following values (errors are random): C-p(0)(298.15K) = 115.09 +/- 0.33 J mol(-1) K-1, S-0(298.15 K) = = 135.98 +/- 0.25 J mol (-1) K-1, and H-0(298.15 K) - H-0(0 K) = 20.581 +/- 0.018 kJ mol(-1). An anomaly of the heat capacity was observed in the range from 170 to 267K; its entropy and enthalpy effects were equal to Delta S-an = = 0. 69 J mol(-1) K-1 and Delta H-an = 1525 mol(-1).