Our calculations suggest there are two factors suggestive of why the zni topology is more stable than the SOD topology for Im-based ZIFs. Firstly, the 4MR-zni cluster is slightly more stable than the 4MR-SOD cluster (-4.74 eV vs. -4.70 eV). But more importantly, the dihedral angle between the four Zn atoms in the 4MR-zni Im cluster (14.5 • , see Figure ) is similar to that of the 4MR in the zni crystal structure (∼ 11 • ), in contrast to that of the mIm-based cluster 4MR-zni (3.3 • ). Thus, the formation of an Im-based SOD topology would lead to a strained, and thus less stable, crystal structure.