The gas-phase infrared spectra of formyl iodide and carbonyl iodide

Medium resolution infrared spectra (Δν = 1 cm−1) have been recorded in the wavenumber range 4000−500 cm−1 of the products formed in the 254 nm gas-phase photolysis of p.p.m. levels of iodoform (CHI3) and NOx at a total pressure of 1013 mbar (N2 + O2) and 298 ± 2 K in a large volume glass reaction chamber. Formyl iodide (OCHI) has been identified as a major photooxidation product and its infrared spectrum is reported. Heating of carbon tetraiodide (CI4) in a stream of oxygen results in the formation of carbonyl iodide (OCI2) and the first infrared spectrum of this compound is reported. Whereas carbonyl iodide was found to be long-lived in the reactor, formyl iodide was observed to decay rapidly within a matter of minutes with the formation of CO.