The ion coordination affinities of the commonly found metal ions were evaluated using DFT calculations. The results indicate that the lowest unoccupied molecular orbital (LUMO) energy of metal ions correlates positively with their binding energies with O(S) ligands, and some metal ions with various valence states also present different affinities. Besides, due to the steric hindrance effects, the mono- and hexa-coordinated metal ions may exhibit different affinities, and the majority of the studied hexa-coordinated metal ions exhibit oxophilicity. These affinity differences perfectly illustrate the activation flotation practice in which the oxyphilic ions are applied to activating oxide minerals, while thiophilic ions are applied to activating sulfide minerals.