fig2

Figure 2. Crystal structures of the La-Sr-H system at 200 GPa. (A) LaSrH_P$$\overline{3}$$m1, (B) LaSrH₄_P6/mmm, (C) LaSrH₈_Pmma, (D) LaSrH₁₂_R3m, (E) LaSr₂H₁₈_C2/m, (F) LaSr₃H₂₄_R$$\overline{3}$$m, and (G) LaSrH₂₁_Cm. Red, gray-violet, and dark-blue balls represent La, Sr, and H atoms, respectively. The bonds between H₂ and H₃ units are represented as black dashed lines.