Figure 1.

Ternary convex hull diagram of the Y–Th–H system at 200 and 300 GPa obtained using Pymatgen’s phase analysis module.⁶⁵ Only the stable phases are shown. Black lines connecting the ternaries indicate the shortest synthesis pathways. Out of three stable compositions YThH₈, Y₂ThH₁₂, and YThH₁₈ was observed at 200 GPa; the YThH₁₈ phase disappeared at 300 GPa.