To develop a detailed picture of the bare Fe-3 cluster structure, the nature of chemical bonding in this metal cluster is investigated by natural bond orbital (NBO) and natural resonance theory (NRI) analyses. The first part of the study clearly shows that the main factor governing the ground-state geometry of this cluster is the delocalized nature of the valence electrons. Highly unsaturated structure and the charge transfer list of Omega(i) -> Omega(j)* NBO interactions of the parent reference Fe-3 structure draw one's attention to the possible candidate structures presenting the correct electronic structure consistent with the observed optimized geometry of Fe-3. In the other part of the study, different established modes of nitrogen coordination on Fe-3 cluster are investigated. It is found that the most favored adsorption site for the associative attachment of N-2 is the bridge site, with the binding energy of -17.6 kcal/mol. NBO analysis is also applied to present a detailed discussion of the metal-ligand interactions and the predominate role of the delocalized valence electrons.