It is clear from that lowering the protonation energy affects the energies of several other steps in the catalytic cycle. To investigate this further we have collect the B3LYP SP reaction energies for all catalysts with 2 neutral ligands (36 catalysts). Due to the structural distortions of the 1 neutral ligand catalysts, these were not considered for this analysis. Following the approach from Busch et al. we then construct the scaling relations between all reactions and the first protonation reaction relative to the resting state which is the Mo N 2 intermediate. The individual scaling relations and their R 2 value can be found in Figure in the SI. We set a cutoff of 0.2 for the coefficient of determination. Scaling relations with R 2 below this value are not considered to be relevant for the first protonation energy. The resulting volcano plot is shown in Figure where each label refers to the resulting intermediate of a reaction. For example: