High-temperature heat capacity and thermodynamic properties for end-member titanite (CaTiSiO 5 )

Abstract

The heat capacity of end-member titanite and (CaTiSiO 5 ) glass has been measured in the range 328–938 K using differential scanning calorimetry. The data show a weak λ-shaped anomaly at 483 ± 5 K, presumably associated with the well-known low-pressure P 2 1 /a ⇆ A 2/a transition, in good agreement with previous studies. A value of 0.196 ± 0.007 kJ mol −1 for the enthalpy of the P 2 1 /a ⇆ A 2/a transition was determined by integration of the area under the curve for a temperature interval of 438–528 K, bracketing the anomaly. The heat capacity data for end-member titanite and (CaTiSiO 5 ) glass can be reproduced within <1% using the derived empirical equations (temperature in K, pressure in bars):