The sound velocity measurements of Fe3S

This is the authors' abstract. We don't add key points for this paper.

We measured the sound velocity of Fe 3 S at room temperature up to 85 GPa employing inelastic X‑ray scattering to better constrain the constitution of the inner core. The density of Fe 3 S was also determined by X-ray diffraction under the same conditions. The relation of the P-wave velocity ( v P ) and density (ρ) of Fe3S follows Birch’s law, v P (m/s) = 1.14(5) × ρ(kg/m3) - 2580(410). Based on Birch’s law determined here for Fe 3 S and that for ε-Fe reported previously, we found that sulfur decreases both density and compressional velocity of hcp-Fe at the core pressure and 300 K.