Heat capacity, entropy, and phase equilibria of dmitryivanovite

摘要: The heat capacity (C p ) of dmitryivanovite synthesized with a cubic press was measured in the temperature range 5–664 K using option physical properties measurement system and differential scanning calorimeter. entropy at standard pressure (STP) calculated to be 110.1 ± 1.6 J mol−1 K−1 from C data. With help new phase equilibrium experiments done 1.5 GPa, transition boundary between krotite best represented by equation: P (GPa) = −2.1825 + 0.0025 T (K). From intercept this other available thermodynamic data for dmitryivanovite, enthalpy formation Gibbs free energy STP were −2326.7 ± 2.1 −2,208.1 ± 2.1 kJ mol−1, respectively. It is also inferred that stable CaAl2O4 has wide stability field high pressures whereas located temperatures relatively low pressures. This conclusion consistent natural occurrences (in Ca–Al-rich inclusions) krotite, where former interpreted as shock metamorphic product originally present krotite.