For example, while HSE06 overestimates the O2 binding strength to Fe-DOBDC, yielding an adsorption energy of -0.39 eV, CCSD(T) predicts it to be repulsive (i.e., unbound) at 0.16 eV. Incorporating exact exchange in DFT calculations significantly alters the adsorption energy range for all of the molecules on SBUs. The adsorption energy calculated using PBE ranges from -0.93 eV to -0.06 eV, while the adsorption energy calculated using HSE06 is shifted upward ranging from -0.39 eV to 0.41 eV, meaning that some interactions are repulsive even when the DFT-D3 dispersion correction is applied. For the HSE06 calculations, the adsorption energy of CO2 exhibits the narrowest range, from -0.37 eV to -0.14 eV. N2 displays a slightly wider range, spanning from -0.36 eV to 0.06 eV. And O2 shows the broadest range, varying from -0.39 eV to 0.41 eV, i.e., the same as the total range over all molecules. Molecules that show small ranges of binding energies tend to display better agreement between PBE and HSE calculations. That is, CO2 adsorption energies have a MAD of only 0.03 eV, the MAD for N2 is higher at 0.13 eV, and O2 demonstrates the largest deviation at 0.26 eV. It is worth noting that the adsorption of O2 is particularly susceptible to self-interaction error arising from a considerable charge transfer from the metal atom to the O2 molecules, 82 leading to erroneous conclusions regarding adsorption behavior. For example, PBE calculations suggest a strong binding of O2 to Fe2Cl2-BBTA with an absorption energy of -0.48 eV, whereas HSE06, which corrects for the impact of SIE, indicates a repulsive interaction, estimating an adsorption energy of 0.17 eV.