Fig. 2. Pressure dependence of the convex hull diagram, colour, and reflectivity of the lutetium–hydrogen binary system.

a Convex hull diagrams as a function of pressure for compositions in the range LuH₀ to LuH₃. Dark blue circles indicate thermodynamically stable structures and red circles indicate metastable structures. The dashed vertical lines for selected stoichiometries are shown for guidance only. b Colour of LuH_n compounds as a function of pressure. c Reflectivity of LuH_n compounds as a function of pressure.