For each model, three calculations were run: a geometry optimization including a numerical frequency calculation to ensure the optimization led to a true local minimum, a single point calculation for precise electronic energies, and a single point calculation for the Mössbauer parameters. This procedure and the individual levels of theory have been applied successfully in previous work including benchmarking studies of spin states and Mössbauer parameters. For all ORCA 5.0.3 calculations, convergence criteria for both geometry optimization and single point calculation were set to "tight" in ORCA nomenclature. The SMD model with water as solvent was used to take environmental effects into account. Split-RI-J approximation for GGA and meta-GGA functionals and RIJCOSX approximation for hybrid functionals both with def2/J auxiliary basis set were used. The DefGrid2-keyword was given to define the integration grid.