We have performed in situ X-ray diffraction experiments on the Fe–S–H system up to 10 GPa and 1673 K at BL04B1. The subsolidus phases were FeHx (x~0.4) and FeSHx (x~0.2) at 5 GPa and FeHx (x~0.9) and FeSHx (x~0.3) at 10 GPa. We found that H depressed the liquidus of Fe–26 wt.% S by 200–300 K whereas its solidus (i.e., eutectic temperature of the Fe–FeS system) did not decrease.
