Isotopically labeled nitrous oxide has been produced in solid nitrogen matrices using mixtures of nitrogen and water containing 14 N , 15 N , 16 O , 17 O , and 18 O . All twelve possible N 2 O isotopomers have been obtained, and their fundamental, overtone and combination frequencies were assigned by the joint use of infrared spectroscopy and quantum chemical calculations (B3LYP/AUG-cc-pVTZ). Specific influence of the nitrogen matrix upon frequency and anharmonicity of the vibrations has been discussed.