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|Section2= |Section3= |Section7= |Section8= }} Tungsten(VI) fluoride, also known as tungsten hexafluoride, is the inorganic compound of tungsten and fluorine with the formula WF6. This corrosive, colorless compound is a gas under standard conditions, with a density of about 13 g/L (roughly 11 times heavier than air.〔(Gas chart )〕〔(【引用サイトリンク】format= pdf )〕), WF6 is one of the heaviest known gases under standard conditions.〔 WF6 gas is most commonly used in the production of semiconductor circuits and circuit boards through the process of chemical vapor deposition – upon decomposition, molecules of WF6 leave a residue of metallic tungsten. This layer serves as low-resistive metallic "interconnect".〔(【引用サイトリンク】title= Tungsten and Tungsten Silicide Chemical Vapor Deposition )〕 ==Properties== At ambient pressure and temperatures above 17 °C, tungsten hexafluoride is a colorless〔 diamagnetic gas. The WF6 molecule is octahedral with the symmetry point group of Oh. The W–F bond distances are 183.2 pm.〔 p. 4-93.〕 Between 2.3 and 17 °C, tungsten hexafluoride condenses into a pale yellow liquid having the density of 3.44 g/cm3 at 15 °C. At 2.3 °C it freezes into a white solid having a cubic crystalline structure, the lattice constant of 628 pm and calculated density 3.99 g/cm3. At −9 °C this structure transforms into an orthorhombic solid with the lattice constants of ''a'' = 960.3 pm, ''b'' = 871.3 pm, and ''c'' = 504.4 pm, and the density of 4.56 g/cm3. In this phase, the W–F distance is 181 pm, and the mean closest intermolecular contacts are 312 pm. Whereas WF6 gas is one of the heaviest gases, with the density exceeding that of the heaviest elemental gas radon (9.73 g/L), the density of WF6 in the liquid and solid state is rather moderate. The vapor pressure of WF6 between −70 °C and 17 °C can be described by the equation :log10 ''P'' = 4.55569 − (1021.208 / (''T'' + 208.45)), where the ''P'' = vapor pressure (bar), ''T'' = temperature (°C).〔Cady, G.H.; Hargreaves, G.B, “Vapour Pressures of Some Fluorides And Oxyfluorides of Molybdenum, Tungsten, Rhenium, and Osmium,” Journal of the Chemical Society, APR 1961, pp. 1568-& DOI: 10.1039/jr9610001568〕〔http://webbook.nist.gov/cgi/cbook.cgi?ID=C7783826&Mask=4&Type=ANTOINE&Plot=on〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Tungsten hexafluoride」の詳細全文を読む スポンサード リンク
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