Molybdenum(V) fluoride  Molybdenum(V) fluoride is an inorganic compound with the formula MoF5. It is a hygroscopic yellow solid. Like most pentafluorides, it exists as a tetramer. Molybdenum(V) fluoride is produced by the reaction of molybdenum and molybdenum hexafluoride:  About 120 °C, it disproportionates to the tetra- and hexafluoride: