1,1,1,2,4,5,5,5-octafluoro-3-(1,2,2,2-tetrafluoro-1-trifluoromethyl-ethyl)-4-trifluoro-methyl-pent-2-ene, perfluoro-3-isopropyl-4-methylpent-2-ene, 1,1,1,2,4,5,5,5-octafluoro-3-[1,2,2,2-tetrafluoro-1-(trifluoromethyl)ethyl]-4-(trifluoromethyl)pent-2-ene, perfluoro-(4-methyl-3-isopropyl-2-pentene), 1,1,1,2,4,5,5,5-octafluoro-3-(1,2,2,2-tetrafluoro-1-trifluoromethyl-ethyl)-4-trifluoromethyl-pent-2-ene, perfluoro-4-methyl-3-isopropyl-2-pentene