Here, the state-0 and state-1 are the Li4RuH6 catalyst surface with active [RuH6] center and the chemisorbed N2 on it ([RuH6]NN), respectively, as presented by the eqn.(3). The state-2 is ([RuH5]NHN), where the adsorbed N2 is hydrogenated by one of the hydrides from the same Ru site where N2 is activated (i.e., H from [RuH6]-NN): State-3 is ([RuH5]NHNH), in which the activated N2 is further hydrogenated by one hydride from neighboring [RuH7]: