Gas phase thermal decomposition of CF3OC(O)OOC(O)F and CF3OC(O)OOCF3 was studied at temperatures between 64 and 98 degrees C (CF3OC(O)OOC(O)F) and 130-165 degrees C (CF3OC(O)OOCF3) using FTIR spectroscopy to follow the course of the reaction. For both substances, the decompositions were studied with N-2 and CO as bath gases. The rate constants for the decomposition of CF3OC(O)OOC(O)F in nitrogen and carbon monoxide fit the Arrhenius equations k(N2) = (3.1 +/- 0.1) x 10(15) exp[-(29.0 +/- 0.5 kcal mol(-1)/RT)] and k(CO) = (5.8 +/- 1.3) x 10(15) exp[-(29.4 +/- 0.5 kcal mol(-1)/RT)], and that for CF3OC(O)OOCF3 fits the equation k = (9.0 +/- 0.9) X 10(13) exp[-(34.0 +/- 0.7 kcal mol(-1)/RT)] (all in units of inverted seconds). Rupture of the O-O bond was shown to be the rate-determining step for both peroxides, and bond energies of 29 +/- 1 and 34.0 +/- 0.7 kcal mol(-1) were obtained for CF3OC(O)OOC(O)F and CF3OC(O)OOCF3. The heat of formation of the CF3-OCO2center dot radical, which is a common product formed in both decompositions, was calculated by ab initio methods as -229 +/- 4 kcal mol(-1). With this value, the heat of formation of the title species and of CF3OC(O)OOC-(O)OCF3 could in turn be obtained as Delta(f)H(298)degrees(CF3OC(O)OOC(O)F) = -286 +/- 6 kcal mol, Delta(f) H(298)degrees(CF3OC(O)OOCF3) = -341 +/- 6 kcal mol(-1), and Delta(f)H(298)degrees(CF3OC(O)OOC(O)OCF3) = -430 +/- 6 kcal mol(-1).