The Fe1-MFU-4l(OH) system (labeled M in the following, see Figure and Figure ) consists of two metal nodes per unit cell, one of which includes an iron center. Each metal node contains four tetrahedral positions and one central octahedral Zn 2+ . Relative energies of the fully optimized structures at the PBE level in spin states S=0, S=1 and S=2 are given in column 2 of Table . It can be seen that the high-spin state has by far the lowest energy. We also performed HSE06 single-point calculations on these geometries. These relative energies are reported in column 3, and again the S=2 spin state has the lowest energy. Finally, we took the geometries obtained for the S=2 spin state with PBE and ran HSE06 single-point calculations at S=0, S=1 and S=2. These relative energies are reported in the last column of Table . Fixing the geometry at the S=2 optimized structure also does not change the trends, so single point comparisons of the optimized structures can be used for estimating the most likely spin state. After loading the S=2 system with one N2O molecule per unit cell, a neglectable expansion of the unit cell (ΔV=17.6 Å 3 or 0.2%) is observed after full relaxation of atomic positions and cell parameters. The cell parameters of this loaded cell are used from here on for all calculations.