And in this case, the fe metal atom is simply too large. It has too large of an electron density around that proton nucleus for that entire metal atom to actually fit snugly in the center of that protoporphine. And so what that means is this fe atom will be found slightly below. Now, in this particular case, this fe atom has 12345 bonds. And what that means is it can form one more bond with some other Atom. And so on.