From 1984 to 1996 there was rapid progress in the spectroscopy of CO₂ dimers and trimers, but since then little work has appeared. Here we report a number of new high-resolution infrared results. For the dimer, a combination band provides the first experimental intermolecular vibrational frequency, and ¹³C isotopic spectra clarify the role of resonant and non-resonant vibrational shifts. For the cyclic trimer, a new parallel combination band involving an out-of-plane intermolecular mode is observed, and various ¹³C isotope results are analysed. In addition to these dimer and trimer results, the spectra also contain features which must be due to larger (CO₂) _N clusters in the range N ≈ 5–15.