1,2-Biradicals as Intermediates in the Cyclodimerization of Tetrafluoroethylene

Using kinetic spectroscopy under strictly homogeneous pyrolysis at temperatures above 800 K, tetrafluoroethylene is shown to convert directly into a 1,2-biradical, the extinction of the latter being estimated to be 2 x 10⁶ cm² mol^–1 at 250 nm. The significance of the biradical is ascertained in the cyclodimerization mechanism and rate constants for elementary reactions are estimated.