BONDING IN C1 AND C2 FLUORIDES

A Farlow-type reaction involving manganese trifluoride and graphite has been used to generate the gaseous species (CF2)n=1,2,3..., CF3, and C2F2 under equilibrium conditions. By mass spectrometric methods it has been found that ΔHf°298 for CF2(g), CF3(g), and C2F2(g) are -41.1 ± 2, -102.5 ± 3, and -45 ± 6 kcal mol-1, respectively. These and other data show that D°298(CF3-F), -(CF2-F), -(CF-F), and -(C-F) are 139.4, 80.2, 123.7, and 126.0 (all ±3) kcal mol-1, respectively. The C=C bond in difluoroacetylene is found to be 60 kcal weaker than that in acetylene.