The lack of a stable (no imaginary frequencies, i.e. a local minimum on the potential energy surface) methyl radical state in the energy plateau region (see Figure and Figure ) could be due to the high spin density located at the oxo oxygen of the MO species (see left side of Figure ). Previously, the creation of an iron-oxyl species has been discussed as promoting activity towards C-H activation and being dependent on a large amount of unpaired electron density at the oxygen atom. The high spin density at the oxo oxygen in our system could, therefore, be responsible for the relatively low energy barrier for H abstraction. Furthermore, we do not observe a stable (local minimum) intermediate involving a methyl radical (see right side of Figure ). The electronic structure of the Fe(OH)2 system here seems to be the reason for this, as we do not observe any charge transfer from or onto the methyl radical, nor any structural changes compared to a free methyl radical. We therefore propose that the high spin density together with the low stability of the Fe(OH)2 system are the main reasons for the observed energy plateau between CH4@MO and CH3OH@M. From this observation, we suggest a single-step reaction mechanism, in contrast to a two-step mechanism involving a stable methyl radical. This could enhance kinetics significantly and thereby lower the chance of CH3 radical desorption. The methanol desorption energy is +28.5 kJ/mol (PBE). In our initial calculations, the bound methanol was oriented with its OH group pointing away from the Fe-OH group after its formation.