Structure of the FeFe-cofactor of the iron-only nitrogenase and possible mechanism for dinitrogen reduction

We use density functional calculations to model the FeFe-cofactor of the iron-only nitrogenase. We determine the ground state geometical and magnetic structure and show that our results are in agreement with experimental observations. We model the reactivity of the FeFeco towards hydrogen and nitrogen and compare to the FeMoco. Our results for the difference in reactivity can be linked to experimental observations.