-fluoride.svg) | |
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| Names | |
|---|---|
| IUPAC names molybdenum(VI) fluoride | |
| Other names molybdenum hexafluoride | |
| Identifiers | |
3D model (JSmol) | |
| ChemSpider | |
| ECHA InfoCard | 100.029.114 |
| EC Number |
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| UNII | |
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| Properties | |
| MoF6 | |
| Molar mass | 209.94 g·mol−1 |
| 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 | |
Othercations | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Molybdenum hexafluoride, alsomolybdenum(VI) fluoride, is aninorganic compound with the formulaMoF6. It is thefluoride ofmolybdenum in its highestoxidation state of +6. It is a colourless solid that melts just belowroom temperature and boils at 34 °C.[3] It is one of the seventeen known binaryhexafluorides.
Molybdenum hexafluoride is made by direct reaction of molybdenum metal in an excess of elementalfluorine:[2]
The compound hydrolyzes easily,[4] and typical impurities areMoO2F2 andMoOF4.[5]
At −140 °C, it crystallizes in theorthorhombic space groupPnma.Lattice parameters area = 9.394 Å,b = 8.543 Å, andc = 4.959 Å. There are fourformula units (in this case, discrete molecules) perunit cell, giving a density of 3.50 g·cm−3.[2] The fluorine atoms are arranged in thehexagonal close packing.[6]
In liquid and gas phase,MoF6 adoptoctahedral molecular geometry withpoint groupOh. The Mo–Fbond length is 1.817 Å.[2]
Molybdenum hexafluoride has few uses. In the nuclear industry,MoF6 occurs as an impurity inuranium hexafluoride since molybdenum is afission product ofuranium.
Thesemiconductor industry constructs variousintegrated circuits throughchemical vapor deposition of molybdenum hexafluoride.[4] In some cases, the deposited molybdenum is an impurity in the intendedtungsten hexafluoride.MoF6 can be removed by reduction of aWF6-MoF6 mixture with any of a number of elements includinghydrogen iodide at moderately elevated temperature.[7][8]
