The reactivity of lanthanide monocations with fluorinated hydrocarbons has been investigated for the first time by using density functional theory. The potential energy surfaces of [Ln, C, H-3, F](+) (Ln = Ce, Pr, and Yb) were explored in detail. A direct abstraction mechanism of fluorine atom by Ln(+) was revealed, and the related thermochemistry data were determined. The electron-transfer reactivities of the reactions were analyzed by the two-state model, and a strongly avoided crossing behavior on the transition state regions for all the three systems was shown. The present results support the reaction mechanism inferred from early experimental data, and the related thermochemistry data given here can provide a guide for further experimental research.