Fig. 1. Escaped hydrogen as a function of pressure. Colored open circles are data points from Refs. 2 and 6. Filled circles represent the maximum n_H at similar pressures and were selected for a second-order polynomial fit (dashed line, R² = 0.96). Only data points with pure or dominant pyrite-type phase were picked for the fit. For example, the two outliers at ∼110 GPa were excluded from the fit because their x-ray diffraction patterns revealed the co-existence of contaminated phases.