Perfluoroisobutene
（重定向自Perfluoroisobutylene）
Perfluoroisobutene (PFIB), also known as 1,1,3,3,3-pentafluoro-2-(trifluoromethyl)prop-1-ene, is a fluorocarbon alkene. It is a hydrophobic reactive gas with boiling point at 7 °C. It is a strong electrophile.
PFIB is about 10 times as toxic as phosgene. Its inhalation can lead to pulmonary edema, which may be fatal. Onset of symptoms can take 1-4 hours after inhalation. Treatment is based on management of the pulmonary edema (usually with high-dose corticoids and other medication/measures) and associated disorders (e.g. heart failure, hypocalcemia etc.). Many cases resolve within 72 hours without major long-term effects.