Copper and silver chloride-nitrous oxide complexes: ClCuNNO and ClAgNNO have been produced and trapped in solid argon by co-deposition of laser-evaporated metal chlorides with nitrous oxide in excess argon. On the basis of isotopic substituted experiments as well as theoretical calculations, infrared absorptions at 2305.8 and 1318.4 cm(-1), and 2291.2 and 1325.4 cm(-1) are assigned to the N-N and N-O stretching modes of the linear ClCuNNO and ClAgNNO complexes, respectively. The binding energies for the complexes with respect to MCl (M = Cu, Ag) and N2O were computationally estimated to be 27.9 and 13.1 kcal/mol. (c) 2005 Elsevier B.V. All rights reserved.