It is interesting to note that the Au I M II 4Cl3(bta)6 structure tended to be highly distorted compared to the other four binding metals, coordinating only with two bta -ligands (Figure ). This behavior agrees with the general tendency of Au I to form linear complexes with coordination number 2. This characteristic might pose significant challenges for materials synthesis. In addition, in H2•••Au I M II 4Cl3(bta)6, the H-H bond is effectively absent, as evidenced by its 2 Å H-H distance, as reported in Table . This leads to square planar coordination and oxidation of the Au I ion to afford the Au III dihydride species (AuH2)M II 4Cl3(bta)6 (Figure ). Such coordination is in accordance with previously observed planar tetracoordinate Au III hydride species. Thus, Au I reacts with H2 via oxidative addition to form an Au III dihydride. The chemical activity of gold toward the cleavage of the H-H bond and the formation of two Au-H bonds might be attributed to the unique chemical properties of this element associated with the relativistic contraction and, as a result, high electronegativity. By contrast, it is noteworthy that Ag I ions tend to form a stable, three-coordinate geometry (Figures ), suggesting stability of the corresponding MOFs. As shown in Table , the activation of an H2 molecule bound to Ag I is less than that of Cu I , as implied by the H-H distance.