The spectrum and photochemistry of carbon suboxide

Abstract

Measurements of the spectra, fluorescence, and photochemical decomposition of aldehydes and ketones containing the chromophoric carbonyl group are already extensive and well known. There is, however, one compound of the same type, possessing a unique structure, which has so far received little attention. This substance, carbon suboxide, is according to the electron diffraction measurements of Pauling and Brockway, linear, and may be written O=C=C=C=O. It thus contains solely a combination of C=O and C=C linkages, the chromophoric and physical properties of each of which have already been investigated experimentally. In addition, the electronic structures and energy levels of these groupings have been studied recently by theoretical methods. We have therefore examined the absorption spectrum and photochemistry of this pentatomic molecule. Since it is gaseous at room temperatures, carbon suboxide has obvious experimental advantages; on the other hand, its tendency to polymerize thermally under ordinary conditions introduces complications into the photochemical measurements. The thermal decomposition of the substance was recently described by Klemenc, Wechsberg, and Wagner, which adds interest to the present work.