R3: High-pressure science and deep Earth’s material

[R3-04] Redetermination of enthalpy of Mg₂SiO₄ wadsleyite

*Hiroshi Kojitani¹, Toru Inoue², Masamichi Noda², Masaki Akaogi³ (1. Gakushuin Univ., Sci., 2. Hiroshima Univ., Advanced Sci. and Eng., 3. Univ. Tokyo, Sci.)

Keywords:wadsleyite, enthalpy, drop-solution calorimetry, thermodynamics, high-pressure synthesis

Scince the previous enthalpy value of Mg₂SiO₄ wadsleyite had relatively large uncertainty, drop-solution enthalpy of Mg₂SiO₄ wadsleyite was re-measured using lead borate solvent and the Calvet-type calorimter whose temperature was kept at 978 K. Drop-solution enthalpy of Mg₂SiO₄ wadsleyite was determined to be 141.38±1.13 kJ/mol. It is expected that thermodynamic calculation using the present enthalpy data gives a narrower stability field of Mg₂SiO₄ wadsleyite than that calculated by adpting the previous enthalpy data.