The reaction of PPN[Fe(CO)3(NO)] (PPN = bis(triphenylphosphin)iminium cation) with Fe3(CO)12 produces the nitrido cluster PPN[Fe4N(CO)12]. The structure was determined by single-crystal X-ray crystallography [PI space group, Z = 2, a = 10.700 (2)Å, b = 14.146 (3)Å, c = 16.249 (3)Å, α = 91.15 (1)°, β = 94.55 (2)°, γ = 97.52 (2)°] and found to contain a butterfly arrangement of iron atoms with the nitrogen situated in the center of the cluster. [Fe4N(CO)12]- reacts with acids giving several products, of which Fe4N(CO)12H is the major derivative. The remaining products, apparently formed when excess acid and free carbon monoxide are present, are Fe4N(CO)11(NO), Fe3(NH)(CO)10, and Fe3(NH)2(CO)9. The last two imido clusters have been characterized by comparison to existing related compounds. The structure of Fe4N(CO)11(NO) likely contains the same Fe4N moiety as [Fe4N(CO)12]-, although other structures are possible. The reaction of NOPF6 with PPN[Fe4N(CO)12] produces Fe4N(CO)11(NO) in 62% yield.