[Fe 2 (µ-O)(NH 3 ) 10 ] 2+ underwent optimization in a two-step procedure. Initially, unrestricted KS-DFT geometry optimizations were performed for the high-spin states, which involve ferromagnetic coupling between the two centers, and these were succeeded by BS-DFT optimizations. This approach guaranteed that subsequent unrelaxed angle scans started from local minima on the corresponding potential energy surfaces. All computations utilized the def2-TZVP basis set, and the construction of Coulomb integrals were sped up using the related def2/J auxiliary basis set. Grimme's D4 dispersion correction was incorporated to address long-range interactions between the metal-oxo bridge and the coordinating ammonia ligands. Geometry optimizations employed the defGrid3 integration grid, with both the SCF and optimization steps being subject to tight convergence criteria (VeryTightSCF, Very-TightOpt). To improve convergence stability, the SlowConv option was utilized throughout the SCF cycles.