- Source: Xenon tetrafluoride
Xenon tetrafluoride is a chemical compound with chemical formula XeF4. It was the first discovered binary compound of a noble gas. It is produced by the chemical reaction of xenon with fluorine:
Xe + 2 F2 → XeF4
This reaction is exothermic, releasing an energy of 251 kJ/mol.
Xenon tetrafluoride is a colorless crystalline solid that sublimes at 117 °C. Its structure was determined by both NMR spectroscopy and X-ray crystallography in 1963. The structure is square planar, as has been confirmed by neutron diffraction studies. According to VSEPR theory, in addition to four fluoride ligands, the xenon center has two lone pairs of electrons. These lone pairs are mutually trans.
Synthesis
Xenon tetrafluoride is produced by heating a mixture of xenon and fluorine in a 1:5 molar ratio in a nickel container to 400 °C. Some xenon difluoride (XeF2) and xenon hexafluoride (XeF6) is also produced, where increased temperature or decreased fluorine concentration in the input mixture favors XeF2 production, and decreased temperature or increased fluorine concentration favors XeF6. The nickel is not a catalyst for this reaction; nickel containers are used because they react with fluorine to form a protective, non-peeling passivation layer of nickel(II) fluoride NiF2 on their interior surfaces. The low volatility of XeF4 compared to XeF2 and XeF6 allows it to be purified by fractional sublimation.
Reactions
Xenon tetrafluoride hydrolyzes at low temperatures to form elemental xenon, oxygen, hydrofluoric acid, and aqueous xenon trioxide:
6
X
e
F
4
+
12
H
2
O
→
2
X
e
O
3
+
4
X
e
↑
+
3
O
2
↑
+
24
H
F
{\displaystyle {\rm {\ 6XeF_{4}+12H_{2}O\rightarrow 2XeO_{3}+4Xe\uparrow +3O_{2}\uparrow +24HF}}}
It is used as a precursor for synthesis of all tetravalent Xe compounds. Reaction with tetramethylammonium fluoride gives tetramethylammonium pentafluoroxenate, which contains the pentagonal XeF−5 anion. The XeF−5 anion is also formed by reaction with cesium fluoride:
CsF + XeF4 → CsXeF5
Reaction with bismuth pentafluoride (BiF5) forms the XeF+3 cation:
BiF5 + XeF4 → XeF3BiF6
The XeF+3 cation in the salt XeF3Sb2F11 has been characterized by NMR spectroscopy.
At 400 °C, XeF4 reacts with xenon to form XeF2:
XeF4 + Xe → 2 XeF2
The reaction of xenon tetrafluoride with platinum yields platinum tetrafluoride and xenon:
XeF4 + Pt → PtF4 + Xe
Applications
Xenon tetrafluoride has few applications. It has been shown to degrade silicone rubber for analyzing trace metal impurities in the rubber. XeF4 reacts with the silicone to form simple gaseous products, leaving a residue of metal impurities.
References
External links
WebBook page for XeF4
Kata Kunci Pencarian:
- Xenon
- Xenon tetrafluorida
- Terbium(IV) fluorida
- Kripton
- Kripton tetrafluorida
- Kamus rumus kimia
- Radon
- Fluorin
- Neptunium
- Xenon tetrafluoride
- Xenon
- Xenon compounds
- Tetrafluoride
- Xenon fluoride
- Noble gas compound
- Xenon trioxide
- Xenon dioxide
- Xenon difluoride
- Molecular symmetry
