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On the basis of latest experimental data and ab-initio calculations the multy-phase equation of state for iron taking into account a, e, y and liquid phases has been constructed and the phase diagram has been calculated. Free energy of solid phases is written as a sum of four terms corresponding to static lattice potential, lattice phonon free energy, magnetic term (for a phase only) and free energy due to thermal exitations of electrons. The last term instead of traditionally used square law was determined using Fermi-Dirac statistics and the one-particle spectrum of a crystal calculated for T=OK. Lattice contribution is described by high-temperature expansion of Debay model and static potential is an approximation of ab-initio calculations and experimental data on static compression.To evaluate the equation of state for a liquid phase we used Grover model. Obtained results are in good agreement with thermophysical, phase boundary and shock wave measurements. Up-to-date ideas about layout of iron phase diagram at high pressures and temperatures have been discussed.

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