Nitrogen fixation is a process in which nitrogen (N2) in the atmosphere is converted into ammonium (NH4+). Atmospheric nitrogen or molecular nitrogen (N2) is relatively inert: it does not easily react with other chemicals to form new compounds. The fixation process frees up the nitrogen atoms from their triply bonded diatomic form, N≡N, to be used in other ways.
More at: Nitrogen fixation
More at: nitrogen fixation