White cubic crystals or colorless volatile liquid; hygroscopic; density 2.54 g/cm3; melts at 17.5°C; boils at 34°C; critical temperature 200°C; critical pressure 46.88 atm; critical volume 226 cm3/mol; reacts with water (hydrolyzed).
Molybdenum(VI) fluoride plays an important role in the semiconductor industry and the nuclear industry.
Separation of molybdenum isotopes.
ChEBI: Molybdenum hexafluoride is a molybdenum halide.
Molybdenum hexafluoride is prepared by passing fluorine over molybdenum powder:
Mo + 3F2 → MoF6.
Purify the hexafluoride by low-temperature trap-to-trap distillation over pre-dried NaF. It is hygroscopic, fumes in moist air and is hydrolysed readily by H2O. [Oppengard et al. J Am Chem Soc 82 3825 1960, Anderson & Winfield J Chem Soc, Dalton Trans 337 1986, Kwasnik in Handbook of Preparative Inorganic Chemistry (Ed. Brauer) Academic Press Vol I p 259 1963.] Poisonous vapours.
