Recent calculations by Montgomery and co-workers(1) suggest that the accepted value for the heat of formation of COF2 is in error by more than 6 kcal mol(-1). Additional calculations reported here support this contention. The revised value for Delta(f)H degrees(298)(COF2) permits a reanalysis of available kinetic and thermodynamic data on the energies of a number of other small fluorine-containing molecules, including CF3O radical, CF3OF, and CF3-OOCF3, and resolves a number of discrepancies between previous calculated and experimental results. It also allows a reevaluation of the energetics of HF loss from CF3OH, an important reaction in the atmospheric degradation of several HFCs.