applying an OEEF of -1 VÅ -1 along the Fe-N2 vector induces a dipole moment of only 0.75D, corresponding to < 2 kcal/mol energetic stabilization (Figure ). A small dipole moment may result from electron transfer to, or from, the FeMo cluster upon coordination. However, due to the large HOMO-LUMO gap of isolated N2, this is presumably a very minor effect: Head-Gordon and co-workers reported a transfer of a mere 0.03 e -from N2 to the catalytic cluster in their advanced electronic structure calculations. The emergence of a minuscule positive charge on N2 upon coordination would lead to an induced dipole that is stabilized by a negative Fz around Fe2. As such, as an isolated event, when all other factors are equal, binding of N2 to Fe2 ought to be favored over binding to Fe6.