A minor controversy has emerged recently over the value of the ionization energy of the trifluoromethyl radical, CF3. Solid evidence appears to support both high values; IEa approximate to 9.05 eV, and low values, IEa approximate to 8.65 eV. Examining the assumptions made in the analysis of the various experimental results shows that the root of the discrepancy is the role of entropy in low-pressure, gas-phase ion chemistry. The proper treatment of entropy has, itself, been a more fundamental controversy for a long time. In the zero-pressure limit, conservation of energy (Delta E) in a molecular collision is the primary consideration, but at the high-pressure limit, the free energy (Delta G) dictates the outcome of a reaction: what pressures qualify as "high"? (Henchman, M.; et al. In Structure/Reactivity and Thermochemistry of Ions; Ausloos, P., Lias, S. G., Eds.; Reidel: Dordrecht, The Netherlands, 1987, pp 381-399). The present paper does not achieve any fundamental resolution of the entropy question. However, it does demonstrate that many discrepancies involving CF3 are eliminated (in favor of the higher values of the ionization energy) when the free energy model is used. This result suggests that entropy remains important at lower pressures than many investigators now presume.