Trifluoromethylsulfur pentafluoride, CF<sub>3</sub>SF<sub>5</sub>, is a rare greenhouse gas. It was first identified in the atmosphere in 2000. Trifluoromethylsulfur pentafluoride is considered to be one of the several "super-greenhouse gases".
The chemistry of this compound is similar to that of sulfur hexafluoride (SF<sub>6</sub>).
On a per molecule basis, it is considered to be the most potent greenhouse gas present in Earth's atmosphere, having a 100-year global warming potential of about 18,000 times that of carbon dioxide. The chemical is predicted to have a lifetime of 800 years in the atmosphere. However, the current concentration of trifluoromethylsulfur pentafluoride remains at a level that is unlikely to measurably contribute to global warming. The presence of the gas in the atmosphere is attributed to anthropogenic sources, possibly a by-product of the manufacture of fluorochemicals, originating from reactions of SF<sub>6</sub> with fluoropolymers used in electronic devices and microchips, or the formation can be associated with high voltage equipment created from SF<sub>6</sub> (a breakdown product of high voltage equipment) reacting with CF<sub>3</sub> to form the CF<sub>3</sub>SF<sub>5</sub> molecule.