Figure 3.
Plot of the Fe-O distance as a function of x-ray dose. Each of the 13 structures was refined exactly the same way using the same starting structure and two different protocols. In the first the distances between the Fe and N atoms (4 pyrrole and 1 His closed circles) were restrained while in the second protocol no restraints were applied (open circles). At no time were restraints imposed on the Fe-O distance. The estimated error in the Fe-O bond distance is ≈0.017Å (see Supporting Information).