Osmium pentafluoride is an inorganic compound with the formula OsF<sub>5</sub>. It is a blue-green solid. Like the pentafluorides of Ru, Rh, and Ir, OsF<sub>5</sub> exists as a tetramer in the solid state.
Osmium pentafluoride can be prepared by reduction of osmium hexafluoride with iodine as a solution in iodine pentafluoride:
It can also be prepared by treating a solution of osmium hexafluoride in anhydrous hydrogen fluoride with hydrogen or silicon. Platinum gauze or UV irradiation increase the reaction rate.