Xenon tetrafluoride is a

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

with

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

. It was the first discovered

binary compound In materials chemistry, a binary phase or binary compound is a chemical compound containing two different elements. Some binary phase compounds are molecular, e.g. carbon tetrachloride (CCl4). More typically binary phase refers to extended soli ...

of a

noble gas The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a class of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low ch ...

. It is produced by the

chemical reaction A chemical reaction is a process that leads to the chemical transformation of one set of chemical substances to another. Classically, chemical reactions encompass changes that only involve the positions of electrons in the forming and breaking ...

xenon Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...

with

fluorine Fluorine is a chemical element with the symbol F and atomic number 9. It is the lightest halogen and exists at standard conditions as a highly toxic, pale yellow diatomic gas. As the most electronegative reactive element, it is extremely reactiv ...

: : Xe + 2 → This reaction is

exothermic In thermodynamics, an exothermic process () is a thermodynamic process or reaction that releases energy from the system to its surroundings, usually in the form of heat, but also in a form of light (e.g. a spark, flame, or flash), electricity ...

, releasing an

energy In physics, energy (from Ancient Greek: ἐνέργεια, ''enérgeia'', “activity”) is the quantitative property that is transferred to a body or to a physical system, recognizable in the performance of work and in the form of ...

of 251 kJ/mol. Xenon tetrafluoride is a colorless

crystal A crystal or crystalline solid is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions. In addition, macro ...

line solid that sublimes at 117 °C. Its structure was determined by both

NMR spectroscopy Nuclear magnetic resonance spectroscopy, most commonly known as NMR spectroscopy or magnetic resonance spectroscopy (MRS), is a spectroscopic technique to observe local magnetic fields around atomic nuclei. The sample is placed in a magnetic fi ...

and

X-ray crystallography X-ray crystallography is the experimental science determining the atomic and molecular structure of a crystal, in which the crystalline structure causes a beam of incident X-rays to diffract into many specific directions. By measuring the angles ...

in 1963. The structure is

square planar The square planar molecular geometry in chemistry describes the stereochemistry (spatial arrangement of atoms) that is adopted by certain chemical compounds. As the name suggests, molecules of this geometry have their atoms positioned at the corne ...

, as has been confirmed by

neutron diffraction Neutron diffraction or elastic neutron scattering is the application of neutron scattering to the determination of the atomic and/or magnetic structure of a material. A sample to be examined is placed in a beam of thermal or cold neutrons to ob ...

studies. According to

VSEPR theory Valence shell electron pair repulsion (VSEPR) theory ( , ), is a model used in chemistry to predict the geometry of individual molecules from the number of electron pairs surrounding their central atoms. It is also named the Gillespie-Nyholm the ...

, 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 Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow t ...

container to 400 °C. Some

xenon difluoride Xenon difluoride is a powerful fluorinating agent with the chemical formula , and one of the most stable xenon compounds. Like most covalent inorganic fluorides it is moisture-sensitive. It decomposes on contact with water vapor, but is otherwis ...

() and

xenon hexafluoride Xenon hexafluoride is a noble gas compound with the formula XeF6. It is one of the three binary fluorides of xenon, the other two being XeF2 and XeF4. All known are exergonic and stable at normal temperatures. XeF6 is the strongest fluorinati ...

() is also produced, where increased temperature or decreased fluorine concentration in the input mixture favors production, and decreased temperature or increased fluorine concentration favors . The nickel is not a

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

for this reaction; nickel containers are used because they react with fluorine to form a protective, non-peeling passivation layer of nickel(II) fluoride on their interior surfaces. The low volatility of compared to and allows it to be purified by fractional sublimation.

Reactions

Xenon tetrafluoride

hydrolyzes Hydrolysis (; ) is any chemical reaction in which a molecule of water breaks one or more chemical bonds. The term is used broadly for substitution, elimination, and solvation reactions in which water is the nucleophile. Biological hydrolysis ...

at low temperatures to form elemental xenon,

oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements ...

hydrofluoric acid Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepres ...

, and aqueous

xenon trioxide Xenon trioxide is an unstable compound of xenon in its +6 oxidation state. It is a very powerful oxidizing agent, and liberates oxygen from water slowly, accelerated by exposure to sunlight. It is dangerously explosive upon contact with organic ma ...

. It is used as a precursor for synthesis of all tetravalent Xe compounds. Reaction with

tetramethylammonium fluoride Tetramethylammonium fluoride is the quaternary ammonium salt with the formula (CH3)4NF. This hygroscopic white solid is a source of “naked fluoride", that is fluoride ions not connected to a metal atom in a complex. Most other soluble salts of f ...

gives tetramethylammonium pentafluoroxenate, which contains the pentagonal anion. The anion is also formed by reaction with

caesium fluoride Caesium fluoride or cesium fluoride is an inorganic compound with the formula CsF and it is a hygroscopic white salt. Caesium fluoride can be used in organic synthesis as a source of the fluoride anion. Caesium also has the highest electropositivi ...

: :CsF + → Reaction with

bismuth pentafluoride Bismuth pentafluoride is an inorganic compound with the formula BiF5. It is a white solid that is highly reactive. The compound is of interest to researchers but not of particular value. Structure BiF5 is polymeric and consists of linear chains ...

() forms the cation: : + → XeF₃BiF₆ The cation in the salt XeF₃Sb₂F₁₁ has been characterized by NMR spectroscopy. At 400 °C, reacts with xenon to form : :XeF₄ + Xe → 2 XeF₂ The reaction of xenon tetrafluoride with

platinum Platinum is a chemical element with the symbol Pt and atomic number 78. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Its name originates from Spanish , a diminutive of "silver". Pla ...

yields

platinum tetrafluoride Platinum tetrafluoride is the inorganic compound with the chemical formula . In the solid state, the compound features platinum(IV) in octahedral coordination geometry. Preparation The compound was first reported by Henri Moissan by the fluorinat ...

and xenon: :XeF₄ + Pt → PtF₄ + Xe

Applications

Xenon tetrafluoride has few applications. It has been shown to degrade

silicone rubber Silicone rubber is an elastomer (rubber-like material) composed of silicone—itself a polymer—containing silicon together with carbon, hydrogen, and oxygen. Silicone rubbers are widely used in industry, and there are multiple formulation ...

for analyzing trace metal impurities in the rubber. reacts with the silicone to form simple gaseous products, leaving a residue of metal impurities.

References

External links

WebBook page for XeF₄
{{DEFAULTSORT:Xenon Tetrafluoride Fluorides Nonmetal halides Xenon(IV) compounds