Successful gas chromatographic elution of a range of diene tricar-bonyl from complexes has been achieved for the first time. Provided that precautions were taken to exclude air and prevent prolonged exposure to light many of those supposedly ‘unstable’ compounds could be gas chroma-tographed at temperatures up to 150[ddot] with no apparent thermal decomposition. Teflon columns employing E-301 methyl silicone gum as stationary phase gave best results, symmetrical gausssian peaks being obtained for most compounds with quantitative response to the microgram level.