High‑Spin Antiferromagnetic B1‑Phase FeO: Implications for the Martian Inner core

Seismic data from the InSight mission reveal that Mars possesses a structure comprising a crust, mantle, and core, with recent studies indicating the existence of a solid inner core. While the composition of the inner core of Mars remains unclear, but some scholars argue that it might be FeO and/or Fe₃C. Here, the thermoelastic properties of high‑spin antiferromagnetic B1‑phase FeO was derived from first‑principles calculations, and the composition of the core was inverted by combining with the previous experimental data. Additionally, the possible light element components in the Martian outer core have also been restricted. These results provide a new starting point for the composition of the Martian core and might have implications for understanding the chemical composition and magnetic evolution of the Mars.