The reaction MgCr2O4 + SiO2 = Cr2O3 + MgSiO3 and the free energy of formation of magnesiochromite (MgCr2O4)

Thermodynamic data for magnesiochromite were obtained by analyzing the reaction MgCr2O4 + SiO2 = Cr2O3 + MgSiO3 in the pressure-time domain. The results were then compared with other published values of thermodynamic properties for orthoenstatite, beta-quartz and eskolaite to derive the entropy and enthalpy of formation of MgCr2O4. The results suggested that the available calorimetrically obtained figure for the entropy of MgCr2O4 was approximately 16 joules per kelvin per mole below the real value.