Man Lianjie, Li Xiang, Boffa Ballaran Tiziana, Zhou Wenju, Chantel Julien, Néri Adrien, Kupenko Ilya, Aprilis Georgios, Kurnosov Alexander, Namur Olivier, Hanfland Michael, Guignot Nicolas, Henry Laura, Dubrovinsky Leonid, Frost Daniel J
Bayerisches Geoinstitut, Universität Bayreuth, Bayreuth, Germany.
European Synchrotron Radiation Facility, Grenoble, France.
Nat Commun. 2025 Feb 25;16(1):1710. doi: 10.1038/s41467-025-56220-2.
Seismic, geodetic and cosmochemical evidence point to Mars having a sulfur-rich liquid core. Due to the similarity between estimates of the core's sulfur content and the iron-iron sulfide eutectic composition at core conditions, it has been concluded that temperatures are too high for Mars to have an inner core. Recent low density estimates for the core, however, appear consistent with sulfur contents that are higher than the eutectic composition, leading to the possibility that an inner core could form from a high-pressure iron sulfide phase. Here we report the crystal structure of a phase with the formula FeS, the iron content of which increases with temperature, approaching the stoichiometry FeS under Martian inner core conditions. We show that FeS has a higher density than the liquid Martian core and that a FeS inner core would crystalize if temperatures fall below 1960 (±105) K at the center of Mars.
地震、大地测量和宇宙化学证据表明火星有一个富含硫的液态核心。由于核心硫含量的估计值与核心条件下铁 - 硫化铁共晶成分之间的相似性，得出的结论是，火星的温度过高，无法形成内核。然而，最近对核心的低密度估计似乎与高于共晶成分的硫含量一致，这导致了一种可能性，即高压硫化铁相可能形成内核。在这里，我们报告了一种化学式为FeS的相的晶体结构，其铁含量随温度增加，在火星内核条件下接近化学计量比FeS。我们表明，FeS的密度高于火星液态核心，如果火星中心温度降至1960（±105）K以下，FeS内核将会结晶。
