The relative rate method was used to measure k(Cl + hexafluorocyclobutene) = (8.88 +/- 0.69) x 10 x 13, k(Cl + octafluorocyclopentene) = (1.02 +/- 0.11) x 10 (12), k(Cl + hexafluoro-1,3- butadiene) = (7.28 +/- 0.99) x 10 (11), k(OH + hexafluorocyclobutene) = (8.6 +/- 1.6) x 10 14, k(OH + octafluorocyclopentene) = (1.01 +/- 0.16) x 10 (13), and k(OH + hexafluoro- 1,3- butadiene) = (9.64 +/- 1.76) x 10 (12) cm(3) molecule (1) s (1) in 700 Torr N-2, or air, diluent at 295 K. The atmospheric lifetimes of hexafluorocyclobutene, octafluorocyclopentene, and hexafluoro- 1,3- butadiene were estimated to be 135, 104, and 1.1 days, respectively. The 100 year time horizon global warming potentials for hexafluorocyclobutene and octafluorocyclopentene are 42 and 28. (C) 2011 Elsevier B. V. All rights reserved.