A new method for ambient catalyst-free nitrogen (N₂) fixation has been developed using water radical cations. The process involves the disproportionation of N₂ by water plasma, which produces economically valuable products: hydroxylamine (NH₂OH) and nitroxyl (HNO). The reaction occurs via a distinctive HONH-HNOH* intermediate and is driven by the coordination of electronically excited N₂ with a water dimer radical cation, (H₂O)₂⁺·. The reaction is carried out under mild ambient conditions and does not require a catalyst. The products are collected in a 76-needle array discharge reactor, yielding 1.14 μg cm⁻² h⁻¹ for NH₂OH and 0.37 μg cm⁻² h⁻¹ for HNO. These products have significant applications, including the production of ammonia, chemical reactions with cysteine, and as neuroprotective agents. The method offers a sustainable and cost-effective alternative to traditional nitrogen fixation methods like the Haber-Bosch process, which requires high temperatures and pressures. The reaction mechanism involves the activation of N₂ through its triplet state by water radical cations, leading to the formation of the HONH-HNOH* intermediate, which then dissociates into NH₂OH and HNO. The process is scalable and can be implemented using low-cost setups, such as a solar-powered system. The study highlights the potential of this method for green nitrogen fixation, offering a new pathway for the sustainable conversion of atmospheric nitrogen into valuable chemicals.A new method for ambient catalyst-free nitrogen (N₂) fixation has been developed using water radical cations. The process involves the disproportionation of N₂ by water plasma, which produces economically valuable products: hydroxylamine (NH₂OH) and nitroxyl (HNO). The reaction occurs via a distinctive HONH-HNOH* intermediate and is driven by the coordination of electronically excited N₂ with a water dimer radical cation, (H₂O)₂⁺·. The reaction is carried out under mild ambient conditions and does not require a catalyst. The products are collected in a 76-needle array discharge reactor, yielding 1.14 μg cm⁻² h⁻¹ for NH₂OH and 0.37 μg cm⁻² h⁻¹ for HNO. These products have significant applications, including the production of ammonia, chemical reactions with cysteine, and as neuroprotective agents. The method offers a sustainable and cost-effective alternative to traditional nitrogen fixation methods like the Haber-Bosch process, which requires high temperatures and pressures. The reaction mechanism involves the activation of N₂ through its triplet state by water radical cations, leading to the formation of the HONH-HNOH* intermediate, which then dissociates into NH₂OH and HNO. The process is scalable and can be implemented using low-cost setups, such as a solar-powered system. The study highlights the potential of this method for green nitrogen fixation, offering a new pathway for the sustainable conversion of atmospheric nitrogen into valuable chemicals.