Gas-phase metal nitrate anions are known to yield a variety of interesting metal oxides upon fragmentation. The aluminum nitrate anion complexes, Al(NO3)(4)(-) and AlO(NO3)(3)(-) were generated by electrospray ionization and studied with collision-induced dissociation and energy-resolved mass spectrometry. Four different decomposition processes were observed, the loss: of NO3-, NO3 center dot, NO2 center dot, and O-2. The oxygen radical ligand in AlO(NO3)(3)(-) is highly reactive and drives the formation of AlO(NO3)(2)(-) upon loss of NO3 center dot, AlO2(NO3)(2)(-) upon NO2 center dot loss, or Al(NO2)(NO3)(2)(-) upon abstraction of an oxygen atom from a neighboring nitrate ligand followed by loss of O-2. The AlO2(NO3)(2)(-) fragment also undergoes elimination of O-2. The mechanism for O-2 elimination requires oxygen atom abstraction from a nitrate ligand in both AlO(NO3)(3)(-) and AlO2(NO3)(2)(-), revealing the hidden complexity in the fragmentation of these clusters.