New phase diagram of hydrogen showing the “D” region (the existence of the DP and SC solid-like states cannot be explicitly prescribed, since the behavior in the “D” region is not straightforward; more data is needed to close this gap). Pressure–temperature profiles of Jupiter and Saturn are indicated by the red and blue dashed lines, respectively. The solid–liquid boundary above 4 GPa and the transition from molecular solid H₂ to atomic solid H are adopted from J. M. McMahon et al. (2012), while the magenta transition from molecular fluid H₂ to atomic fluid H is based on R. Helled (2019).