Fig. 2. Metal–silicate partitioning of hydrogen.
a Partition coefficient D (by weight) for hydrogen as a function of reciprocal temperature. The present experiments (red circles) show that hydrogen is strongly siderophile under conditions of Earth’s core formation. Recent experimental studies (gray diamonds11, orange squares12) reported D values lower by one to three orders of magnitude than the present results, which is likely attributed to hydrogen loss from metals during decompression. Pioneer experimental results8 (blue inverted triangles) and recent theoretical values (star13, pink crosses15, and blue pluses14 for H and green pluses14 for H2O; large and small symbols indicate maximum and minimum values, respectively) are also plotted. b Exchange coefficient KD for Eq. 2. The numbers given to each datum point and regression line indicate pressure conditions.