Names | |
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IUPAC names
molybdenum(VI) fluoride
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Other names
molybdenum hexafluoride
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Identifiers | |
3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.029.114 |
EC Number |
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PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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Properties | |
MoF6 | |
Molar mass | 209.93 g/mol |
Appearance | white crystals[1] or colorless liquid hygroscopic |
Density | 3.50 g/cm3[2] |
Melting point | 17.5 °C (63.5 °F; 290.6 K)[1] |
Boiling point | 34.0 °C (93.2 °F; 307.1 K)[1] |
hydrolyzes | |
−26.0·10−6 cm3/mol | |
Structure | |
Orthorhombic, oP28 | |
Pnma, No. 62 | |
octahedral (Oh) | |
0 | |
Related compounds | |
Other cations
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Tungsten hexafluoride Uranium hexafluoride Molybdenum(VI) chloride |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Molybdenum hexafluoride, also molybdenum(VI) fluoride, is the inorganic compound with the formula MoF6. It is the highest fluoride of molybdenum. It is a colourless solid and melts just below room temperature and boils in 34 °C.[3] It is one of the seventeen known binary hexafluorides.
Molybdenum hexafluoride is made by direct reaction of molybdenum metal in an excess of elemental fluorine:[2]
The compound hydrolyzes easily,[4] and typical impurities are MoO2F2 and MoOF4.[5]
At −140 °C, it crystallizes in the orthorhombic space group Pnma. Lattice parameters are a = 9.394 Å, b = 8.543 Å, and c = 4.959 Å. There are four formula units (in this case, discrete molecules) per unit cell, giving a density of 3.50 g·cm−3.[2] The fluorine atoms are arranged in the hexagonal close packing.[6]
In liquid and gas phase, MoF6 adopt octahedral molecular geometry with point group Oh. The Mo–F bond length is 1.817 Å.[2]
Molybdenum hexafluoride has few uses. In the nuclear industry, MoF6 occurs as an impurity in uranium hexafluoride since molybdenum is a fission product of uranium.
The semiconductor industry constructs various integrated circuits through chemical vapor deposition of molybdenum hexafluoride.[4] In some cases, the deposited molybdenum is an impurity in the intended tungsten hexafluoride. MoF6 can be removed by reduction of a WF6-MoF6 mixture with any of a number of elements including hydrogen iodide at moderately elevated temperature.[7][8]
Binary hexafluorides | |||||||||
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Known binary hexafluorides |
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Predicted binary hexafluorides |
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Mo(0) | |
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Mo(II) | |
Mo(III) |
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Mo(IV) | |
Mo(V) | |
Mo(VI) |