As the most abundant constituent in Earth's atmosphere, dinitrogen (N2) is the main nitrogen source of N-containing compounds in the Earth. Therefore, N2 fixation and activation are essential both for nature and humans. Nevertheless, the high bond dissociation energy (942 kJ/mol) and large HOMO-LUMO gap (10.82 eV) make N2 exhibit extremely low reactivity and may be regarded as an inert gas.
