Atomic configurations of 4H2 molecules attached to the backbone structure. The backbone is (A) Fe-decorated, OH-functionalized terphenyl dicarboxylate (TPDC), and (B) V-decorated, OH-functionalized TPDC, respectively, where TPDC is the linker part of the IRMOF16. The blue, gray, red, green, and orange balls stand for hydrogen, carbon, oxygen, iron, and vanadium atoms, respectively.