Spectroscopy of Gaseous Carbonyls. I. Infrared Spectra and Thermodynamic Properties of Chromium and Molybdenum Hexacarbonyls

Infrared spectra of gaseous chromium and molybdenum hexacarbonyls were obtained. The spectra could be interpreted as resulting from an X (YZ)6-type molecule of Oh-symmetry. Of the thirteen fundamental vibration frequencies possible, all but three are fairly well established. The fundamentals are shown to be of two distinct types: (1) those which are typical of a heavy outer atom octahedral molecule and (2) those which are typical of the carbon and oxygen moving in opposition to each other. Thermodynamic properties are computed for the ideal gases for various temperatures to 600°K.