The nitrogen acids RC(O)NHNO2, N-nitroamide, R = CH3 (1), C2H5 (2) and N-nitrocarbamate, R'OC(O)NHNO2, R' = CH3 (3), C2H5 (4) are a class of primary N-nitrocarboxamide compounds that oxidatively add to trans-Ir-(I)(Cl)(N-2)(PPh3)(2) to give six-coordinate Ir-(III)(eta(2)-(NO2)-nitrogen acid)(H)(Cl)(PPh3)(2) complexes 5-8. Unexpected fluxional behavior of the complexes in solution is observed by H-1 NMR spectroscopy. Reaction intermediates of the oxidative addition reactions were also observed and monitored using P-31 and H-1 NMR and solution IR spectroscopies. Complex 5 reacts with methyl triflate in CH3CN to generate bis(acetonitrile) complex (9) from a net loss of the nitrogen acid anion. P(CH3)(2)Ph reacts with 5 to give phosphine-substituted and P(CH3)(2)Ph addition isomers (10). Reactivity studies of 5 with CO gave metastable CO adduct isomer 11, which loses CO on prolonged standing in solution.