While direct electrochemical ammonia production represents the Holy Grail, the documented yields remain very far from any kind of commercialization . The discovery of efficient heterogeneous or homogeneous catalysts that exhibit high activity under mild conditions would thus be a key enabler for the decentralized production of green ammonia. For industrial ammonia synthesis, it is widely recognized that Ru-based catalysts work better than Fe-based catalysts under milder reaction conditions . However, the high activation energy for direct N2 dissociation and the severe poisoning effect of hydrogen on conventional Ru metal catalyst renders efficient NH3 synthesis under lower temperatures (< 623 K) and lower pressures (< 50 bar) unattainable . Therefore, many attempts to develop new catalysts for efficiently catalyzing N2+H2 to NH3 under mild conditions . Recently discovered, a new class of ammonia catalysts -the ternary ruthenium complex hydrides is a breakthrough in this endeavor. The ternary ruthenium hydride's ability to efficiently synthesize NH3 at <10 bar and < 573 K conditions lies in the unique chemistry of the coordination complex and the alkali (alkaline earth) metal framework, facilitating a catalytic mechanism bridging homogeneous and heterogeneous concepts, which are clearly distinct from the Ru metal catalyst. For ternary Ru complex hydride catalysts, Ru is in an ionic state, and N2 undergoes non-dissociative hydrogenolysis over the hydride(H -)-rich and electron-rich [RuH6] 4-complex with the aid of the surrounding Li or Ba cations. The dynamic and synergistic engagement of all the components of the ternary hydrides creates a reaction path with a narrow energy span and leads to ammonia production with superior activities.