Matrix-Isolation Study of the Reaction of Atomic and Molecular Fluorine with Carbon Atoms. The Infrared Spectra of Normal and 13C-Substituted CF2 and CF3

Carbon atoms, resulting from the photolysis of cyanogen azide, are found to react with molecular fluorine in an argon matrix at 14°K to produce CF₂. The use of carbon‐13 has led to confirmation of the previous assignment of features at 1073 and 1191 cm⁻¹ to ¹³CF₂ present in natural abundance. Using recent structural data on CF₂ and the ¹²CF₂ and ¹³CF₂ frequencies, it has been possible to calculate the complete valence force potential of CF₂. Values of the potential constants are compared with those of the related species NF₂ and OF₂. When the sample is subjected to radiation of wavelengths effective in photolyzing F₂, CF₃ is also produced. Sufficient yields of both ¹²CF₃ and ¹³CF₃ have been obtained for observation of all four vibrational fundamentals. Data have been fitted to a four‐constant valence force potential. Agreement is most satisfactory for a $C_{\text{3v}}$ structure with a deviation of 13° from planarity. Using this structure, the thermodynamic properties of CF₃ have been estimated.