If one substitutes in two nickel atoms instead, one gets the three structures AC, BC and BD. AC and BD both present cases in which the nickel has clustered along the bridge/CUS lines, whereas BC presents the case where it clusters across from bridge to CUS. Again the structures with nickel in the bridge positions become interesting when looking for active lattice oxygen. Compared to the pure structure AC presents two bridge site oxygen that are weakly bound (compared to the pure case). Position 1 is weakened to the point that it is slightly weaker than the ideal case. Position 3 presents an oxygen bound at a strength comparable to the position 1 oxygen of structure A. In the case of structure BC positions 1 and 3, the bridge sites neighboring nickel, are also severely weakened. In fact it is a common trend throughout all the structures presented that a Ru-Ni bridge site weakens the bridge site oxygen enough to be potentially active at higher potentials. Additionally, a Ni-Ni bridge site oxygen is bound even weaker, to the point that it might be expected to be an ordinary active site of the surface. These trends can also be observed in the structures with three nickel substitutions: ABC, BCD, ABD, ACD, ACE, BDF. Finally, it is worth it to note that surrounding a subsurface oxygen with Ni (position 8 of structure BCD) destabilizes it enough that a high potential could perhaps make it reactive.