- , calculated with three types of calculations, namely the periodic meta-GGA exchange-correlation functional SCAN+rVV10, with the GFN2-xTB method, and with the non-periodic, hybrid exchange-correlation functional ωB97X/6-311++G(d,p). Each line represents a fitting of the cluster energies corresponding to a particular value of z (with different number of ligands, l). The black circles correspond to the energies of the clusters with z > 8. Red empty circles correspond to the energies of the crystalline materials calculated with the GFN2-xTB method (zni, cri, coi, ZIF-1, ZIF-4, ZIF-6, ZIF-8, SALEM-2, and ZIF-10). Empty triangles correspond to fitted ∆g of the corresponding cluster calculated with the periodic meta-GGA exchange-correlation functional SCAN+rVV10. These values are obtained following the methods described in the ESI. The inset shows the region of larger clusters and of periodic systems.