Reactions of laser-ablated U atoms with N-2 molecules in excess argon during co-deposition at 4 K gave intense NUN and weaker UN absorptions. Annealing increased progressions of new absorptions for the NUN(NN)(1,2,3,4,5) and NU(NN)(1,2,3,4,5,6) uranium nitride complexes. Small matrix shifts are observed when the secondary coordination layers around the primary NUN(NN)(1,2,3,4,5) and NU(NN)(1,2,3,4,5,6) complexes are changed from argon to *nitrogen: Electronic structure and energy and frequency calculations provide support for the identification of these complexes and further characterization of the N equivalent to U equivalent to N and UN core molecules as terminal uranium nitrides with full triple bonds.