- Hexafluoride
s.
Most hexafluorides are
molecular compounds with low melting andboiling point s. Four hexafluorides (S, Se, Te, and W) are gases at room temperature (25 °C) and a pressure of 1 atm, one is a liquid (Re), and the others are volatile solids. Thep-block and group 6 hexafluorides are colorless, but the other hexafluorides have colors ranging from yellow to orange, red, brown, and black.calculations, ReF6 and RuF6 should have tetragonally distorted structures (where two of the bonds along one axis are longer or shorter than the other four), but this has not been verified experimentally.
The hexafluorides have a wide range of chemical reactivity.
Sulfur hexafluoride is nearly inert and non-toxic. It has several applications due to its stability, dielectric properties, and high density (it is the densest non-toxic gas).Selenium hexafluoride is nearly as unreactive as SF6, buttellurium hexafluoride is toxic, not very stable and can be hydrolyzed by water within 1 day. In contrast, metal hexafluorides are corrosive, readily hydrolyzed and may react violently with water. Some of them can be used asfluorinating agent s. The metal hexafluorides have a highelectron affinity , which makes them strong oxidizing agents.Platinum hexafluoride in particular is notable for its ability to oxidize thedioxygen molecule, O2, to formdioxygenyl hexafluoroplatinate , and for being the first compound that was observed to react with xenon (seexenon hexafluoroplatinate ).Some metal hexafluorides find applications due to their volatility.
Uranium hexafluoride is used in theuranium enrichment process to produce fuel fornuclear reactor s.Fluoride volatility can also be exploited fornuclear fuel reprocessing .Tungsten hexafluoride is used in the production ofsemiconductors through the process ofchemical vapor deposition .The table below lists the main physical and structural properties of the hexafluorides.
References
*Greenwood&Earnshaw
*cite journal |doi=10.1021/ic052029f |year=2006 |month=May |author=Drews, T; Supeł, J; Hagenbach, A; Seppelt, K |title=Solid state molecular structures of transition metal hexafluorides |volume=45 |issue=9 |pages=3782–3788 |pmid=16634614 |journal=Inorganic chemistry
* Kirss, Rein U., Lamartine Meda. "Chemical Vapor Deposition of Tungsten Oxide." "Applied Organometallic Chemistry" 12 (1998): 155–160.
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