The photolysis of vinyl fluoride at 1470 Å and pressures in the range 1–150 torr, yields in addition to C2H2 and C2HF, 1,1‐C2H2F2. The yield of 1,1‐C2H2F2 with respect to that of C2H2, increases rapidly with decreasing pressure. It is proposed that F atoms are liberated as a result of the decomposition of certain excited C2H3F molecules. The F atoms in turn react with C2H3F to give a chemically activated difluoroethyl radical with a small excess energy with respect to a decomposition which yields almost exclusively 1,1‐C2H2F2. The details of this preliminary proposal are discussed in relation to the measured relative yields of C2H2, C2HF, and 1,1‐C2H2F2.

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