Crystal structure geometries were refined by optimizing the atomic positions of hydrogen atoms, in either the singlet or doublet state. Optimizations were carried out using Gaussian09 (revision D.01) 43 at the B3LYP*-D3(BJ)/def2-SVP level. B3LYP* is a reparametrized version of B3LYP that reduces Hartree-Fock exchange from 20 % to 15 %, and was shown to improve the description of spin-splitting energetics in TM complexes. Single point computations were then performed at the B3LYP*-D3(BJ)/def2-TZVP level for three different spin states: singlet, triplet, and quintet for systems with an even number of electrons, and doublet, quartet, and sextet otherwise. The spin state with the lowest energy was assigned as the ground state spin. B3LYP* results were compared to two other functionals, TPSSh and M06L, which have also demonstrated good performance in describing splitting energies in spin-crossover Fe complexes. Except for sensitive cases (vide infra), consistent ground state spins were observed with all three levels (see Figure in the SI).