Thionyl fluoride
Encyclopedia
Thionyl fluoride is the inorganic compound
with the formula
S
O
F
2. This colourless gas is mainly of theoretical interest, but it is a product of the degradation of sulfur hexafluoride
, an insulator in electrical equipment. The molecule adopts a pyramidal structure, with C2v symmetry
. The S-O and S-F distances are 1.42 and 1.58 A, respectively. The O-S-F and F-S-F angles are 106.2 and 92.2°, respectively. Thionyl chloride
and thionyl bromide
have similar structures, although these compounds are liquid at room temperature. Mixed halides are also known, such as SOClF.
with fluoride sources such as antimony trifluoride
.
Alternatively, it arises via the fluorination of sulfur dioxide
:
Thionyl fluoride arises as a fleeting intermediate from the decomposition of sulfur hexafluoride as the result of electrical discharges which generate sulfur tetrafluoride
. SF4 hydrolyzes to give thionyl fluoride, which in turn hydrolyzes further as described below.
As expected from the behavior of the other thionyl halides, this compound hydrolyzes readily, giving hydrogen fluoride
and sulfur dioxide
:
In contrast to thionyl chloride and bromide, thionyl fluoride is not useful in organofluorine chemistry
. The related derivative, sulfur tetrafluoride
is however a useful reagent
.
Inorganic compound
Inorganic compounds have traditionally been considered to be of inanimate, non-biological origin. In contrast, organic compounds have an explicit biological origin. However, over the past century, the classification of inorganic vs organic compounds has become less important to scientists,...
with the formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
S
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
O
Oxygen
Oxygen is the element with atomic number 8 and represented by the symbol O. Its name derives from the Greek roots ὀξύς and -γενής , because at the time of naming, it was mistakenly thought that all acids required oxygen in their composition...
F
Fluorine
Fluorine is the chemical element with atomic number 9, represented by the symbol F. It is the lightest element of the halogen column of the periodic table and has a single stable isotope, fluorine-19. At standard pressure and temperature, fluorine is a pale yellow gas composed of diatomic...
2. This colourless gas is mainly of theoretical interest, but it is a product of the degradation of sulfur hexafluoride
Sulfur hexafluoride
Sulfur hexafluoride is an inorganic, colorless, odorless, and non-flammable greenhouse gas. has an octahedral geometry, consisting of six fluorine atoms attached to a central sulfur atom. It is a hypervalent molecule. Typical for a nonpolar gas, it is poorly soluble in water but soluble in...
, an insulator in electrical equipment. The molecule adopts a pyramidal structure, with C2v symmetry
Symmetry group
The symmetry group of an object is the group of all isometries under which it is invariant with composition as the operation...
. The S-O and S-F distances are 1.42 and 1.58 A, respectively. The O-S-F and F-S-F angles are 106.2 and 92.2°, respectively. Thionyl chloride
Thionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...
and thionyl bromide
Thionyl bromide
Thionyl bromide is the chemical compound SOBr2. It is less stable and less widely used than its chloride analogue, thionyl chloride. It is prepared by the action of hydrogen bromide on thionyl chloride, a characteristic reaction where a stronger acid is converted to a weaker acid:Thionyl bromide is...
have similar structures, although these compounds are liquid at room temperature. Mixed halides are also known, such as SOClF.
Synthesis and reactions
Thionyl fluoride can be produced by the reaction of thionyl chlorideThionyl chloride
Thionyl chloride is an inorganic compound with the formula SOCl2. It is a reactive chemical reagent used in chlorination reactions. It is a colorless, distillable liquid at room temperature and pressure that decomposes above 140 °C. Thionyl chloride is sometimes confused with sulfuryl...
with fluoride sources such as antimony trifluoride
Antimony trifluoride
Antimony trifluoride is the inorganic compound with the formula SbF3. Sometimes called Swart's reagent, is one of two principal fluorides of antimony, the other being SbF5. It appears as a white solid...
.
- 3 SOCl2 + 2SbF3Antimony trifluorideAntimony trifluoride is the inorganic compound with the formula SbF3. Sometimes called Swart's reagent, is one of two principal fluorides of antimony, the other being SbF5. It appears as a white solid...
→ 3SOF2 + 2SbCl3Antimony trichlorideAntimony trichloride is the chemical compound with the formula SbCl3. The soft colorless solid with a pungent odor was known to the alchemists as butter of antimony.-Preparation:...
Alternatively, it arises via the fluorination of sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
:
- SO2 + 2PF5Phosphorus pentafluoridePhosphorus pentafluoride, PF5, is a phosphorus halide. It's a colourless gas at room temperature and pressure.-Structure:Single-crystal X-ray studies indicate PF5 molecule has two distinct P−F bonds : P−Fax = 158.0 pm and P−Feq = 152.2 pm...
→ SOF2 + POF3
Thionyl fluoride arises as a fleeting intermediate from the decomposition of sulfur hexafluoride as the result of electrical discharges which generate sulfur tetrafluoride
Sulfur tetrafluoride
Sulfur tetrafluoride is the chemical compound with the formula SF4. This species exists as a gas at standard conditions. It is a corrosive species that releases dangerous HF upon exposure to water or moisture...
. SF4 hydrolyzes to give thionyl fluoride, which in turn hydrolyzes further as described below.
As expected from the behavior of the other thionyl halides, this compound hydrolyzes readily, giving hydrogen fluoride
Hydrogen fluoride
Hydrogen fluoride is a chemical compound with the formula HF. This colorless gas is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the...
and sulfur dioxide
Sulfur dioxide
Sulfur dioxide is the chemical compound with the formula . It is released by volcanoes and in various industrial processes. Since coal and petroleum often contain sulfur compounds, their combustion generates sulfur dioxide unless the sulfur compounds are removed before burning the fuel...
:
- SOF2 + H2O → HF + SO2
In contrast to thionyl chloride and bromide, thionyl fluoride is not useful in organofluorine chemistry
Organofluorine chemistry
Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain the carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil- and water-repellents to pharmaceuticals, refrigerants and reagents in catalysis...
. The related derivative, sulfur tetrafluoride
Sulfur tetrafluoride
Sulfur tetrafluoride is the chemical compound with the formula SF4. This species exists as a gas at standard conditions. It is a corrosive species that releases dangerous HF upon exposure to water or moisture...
is however a useful reagent
Reagent
A reagent is a "substance or compound that is added to a system in order to bring about a chemical reaction, or added to see if a reaction occurs." Although the terms reactant and reagent are often used interchangeably, a reactant is less specifically a "substance that is consumed in the course of...
.