Matrix Isolation Study of the Reaction of Cl Atoms with CO. The Infrared Spectrum of the Free Radical ClCO

Cl atoms have been produced by the photolysis of HCl, Cl2, Cl2CO, and (ClCO)2 in a matrix at 14°K. These atoms are found to react with CO with essentially zero activation energy, producing the previously unobserved free radical ClCO. The vibrational fundamentals of this species have been observed at 281, 570, and 1880 cm−1. Assuming that the ClCO valence angle is 120° or 135° and that the bond distances are similar to those observed for Cl2CO, it is possible to estimate force constants and to calculate frequencies for Cl13CO in reasonable agreement with those observed for this species. The C=O bond is found to possess partial triple-bond character. The thermodynamic properties of ClCO have also been estimated. No ultraviolet absorptions have been observed for this species in the region between 4500 and 2500 Å.