Both computational approaches -molecular and periodic models-thus predict an intermediate spin state for squareplanar iron environments, despite differences in the specifics of the orbital occupation pattern in the pyrrolic case. An intermediate spin state is expected for square-planar coordination environments from ligand field theory considerations, and emphasizes that the computational treatment of the carbon environment does not influence the energetically preferred spin state. We thus conclude that assignments of a high-spin species observed experimentally cannot be made to FeNC models without axial ligands or a significant curvature of the carbon environment. sites. These signatures cannot be explained by our fourfold-coordinate iron(II) models, where high spin states are strongly destabilized. Therefore, we investigated models with an additional axial ligand. Fivefold coordinated complexes such as [Fe(TPP)(2-MeHIm)] and [Fe(TPP)(Cl)] have been discussed in the literature as model complexes for FeNC catalysts and as active catalysts themselves. While these specific axial ligands may not be present in FeNC catalysts obtained by pyrolysis, they are representative in terms of ligand field strength and type of interaction that can be reasonably expected in the real catalysts. As the reference systems in the literature are neutral, we also assumed an overall neutral charge for our model systems.