Clusters of the form NH4(NH3)n have been generated by neutralizing a fast beam of ions in the electron transfer reaction NH4(NH3)n+ K(g) → NH4(NH3)n+ K+ (n = 1-3). Analysis of neutral beam scattering profiles and collisionally reionized mass spectra for NH4(NH3) and ND4(ND3) indicate that these clusters are formed in a distribution of metastable and dissociative states. The n = 1 cluster in its dissociative state has sufficient internal energy to break up to 2NH3 + H without formation of the dimer (NH3)2. The species N2D6H decomposes by preferential loss of a H atom analogous to the dissociative behavior of ND3H. The lifetimes of the metastable states of NH4(NH3) and ND4(ND3) are greater than 1 μs. From thermodynamic considerations the ionization potential of NH4(NH3) is estimated to be 4.0 ± 0.2 eV. As n increases, the ionization potentials for the clusters decrease to a value of about 2.5 eV for NH4(NH3)3. Spectroscopic considerations suggest that NH4(NH3) and ND4(ND3) will exhibit an electronic absorption spectrum involving low-lying Rydberg states.