The reaction of 4,4,4-trifluorobutanethiol on Mo(110) was studied using temperature-programmed reaction, Auger electron, and infrared spectroscopies. The chemistry of trifluoro-1-butanethiol on clean Mo(110) at saturation coverage closely resembles the chemistry observed for 1-butanethiol and trifluoroethanethiol, but there are important differences arising from the presence of fluorine and the length of the alkyl chain. The dominant decomposition pathway for CH3(CH2)(3)S-, CF3(CH2)(3)S-, and CF3CH2S- is C-S bond hydrogenolysis at approximately 300 K to form butane, trifluorobutane, and trifluoroethane, respectively. A secondary pathway is alkene elimination from CH3(CH2)(3)S-, CF3(CH2)(3)S-, and CF3CH2S- to form butene, trifluorobutene, and difluoroethylene, respectively, over a wide temperature range, 200-550 K. The primary difference in the chemistry comparing the two C-4 thiolates, the fluorinated and nonfluorinated, is the observation of difluoroethylene from CF3(CH2)(3)S- at 540 K. No ethylene or other hydrocarbon products were formed at such high temperatures in the reactions of CH3(CH2)(3)S-. The observation of difluoroethylene from the reaction of CF3(CH2)(3)S- is most likely due to a difference in the competing rates of complete decomposition and selective elimination. The increased strength of C-F relative to C-H bonds, and the increased strength of the C-C and C-H bonds adjacent to the trifluoromethyl group, may help to preserve a fluorocarbon intermediate, possibly trifluoroethyl, up to the more elevated temperatures such that difluoroethylene is formed. In addition, calculations suggest that the reaction of trifluorobutanethiol yielding difluoroethylene is thermodynamically more favorable. The chemistry of C-2- and C-4-fluorinated thiolates is also compared and interpreted in terms of both geometric and energetic factors.