Thermodynamics of iron at extreme pressures and temperatures

Abstract

A thermodynamic database on all iron phases (BCC, FCC, HCP and melt) has been created using thermochemical and equations of state data from experiments and theory. The database permits the calculation of the phase diagram of iron to physical conditions of the Earth's core (pressure of 365GPa and temperature of 6453K). If the inner core were all iron, its upper temperature would be 6453 (500)K. The average heat capacity of a pure iron HCP inner core is calculated as 29.4J/mol/K with an entropy of 92J/mol/K and a gruneisen parameter of 1.81.