Nitrogenation for the intermetallic compounds such as MFe2 (M = Ti, Zr, Nb, and Mo) or M'Fe (M' = Ti and V) and the subsequent hydrogenation for the resulting interstitial metal nitrides were carried out to characterize their nitrogen storage properties by heating in a NH3-H-2 mixed gas or N-2 gas at 450-500 degrees C for the former reaction and in H-2 gas at 450 degrees C for the latter one, respectively. Among the intermetallic compounds, the Laves-type MFe2 and the CrFe-type VFe compounds absorbed large amounts of nitrogen into their crystal lattices to transform into amorphous-like a-MFe2Nx and a-VFeNx. They reversibly desorbed nitrogen by the following hydrogenation with maintaining the amorphous-like structure. Qualitative and quantitative analyses of the nitrogen species generated in the desorption step revealed that most of the nitrogen released from the metal nitrides readily reacted with hydrogen to produce ammonia owing to the high reactivity of the atomic nitrogen stored in the intermetallic compounds. Furthermore, the amorphous-like a-TiFe2Nx-delta derived by the nitrogenation in the NH3-H-2 mixed gas and the subsequent hydrogenation in H-2 gas absorbed nitrogen even in N-2 gas at 500 degrees C as loaded with a Ru/Al2O3 catalyst on the surface. The nitrogen stored was also reversibly desorbed as ammonia, suggesting that the molecular nitrogen was converted to ammonia under ambient pressure via the nitrogen absorption -desorption cycle of (Ru/Al2O3/a-TiFe2Nx)/(Ru/Al2O3/a-TiFe2Nx-delta).