Antimony trifluoride is the
inorganic compound with the formula SbF
3. Sometimes called Swarts' reagent, is one of two principal
fluorides of
antimony
Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient t ...
, the other being
SbF5. It appears as a white solid. As well as some industrial applications, it is used as a
reagent in inorganic and
organofluorine chemistry.
Preparation and structure
In solid SbF
3, the Sb centres have
octahedral molecular geometry and are linked by
bridging fluoride
ligands. Three Sb–F bonds are short (192 pm) and three are long (261 pm). Because it is a polymer, SbF
3 is far less volatile than related compounds AsF
3 and SbCl
3.
SbF
3 is prepared by treating
antimony trioxide with
hydrogen fluoride:
:Sb
2O
3 + 6 HF → 2 SbF
3 + 3 H
2O
The compound is a mild
Lewis acid, hydrolyzing slowly in water. With fluorine, it is oxidized to give
antimony pentafluoride.
:SbF
3 + F
2 → SbF
5
Applications
It is used as a
fluorination
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, ...
reagent in
organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, and reactions of organic compounds and organic materials, i.e., matter in its various forms that contain carbon atoms.Clayden, ...
. This application was reported by the Belgian chemist
Frédéric Jean Edmond Swarts in 1892, who demonstrated its usefulness for converting chloride compounds to
fluorides. The method involved treatment with antimony trifluoride with
chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
or with
antimony pentachloride
Antimony pentachloride is a chemical compound with the formula SbCl5. It is a colourless oil, but typical samples are yellowish due to dissolved chlorine. Owing to its tendency to hydrolyse to hydrochloric acid, SbCl5 is a highly corrosive substa ...
to give the active species antimony trifluorodichloride (SbCl
2F
3). This compound can also be produced in bulk. The
Swarts reaction
Swarts fluorination is a process whereby the chlorine atoms in a compound – generally an organic compound, but experiments have been performed using silanes – are replaced with fluorine, by treatment with antimony trifluoride in the presence o ...
is generally applied to the synthesis of
organofluorine compounds, but experiments have been performed using
silane
Silane is an inorganic compound with chemical formula, . It is a colourless, pyrophoric, toxic gas with a sharp, repulsive smell, somewhat similar to that of acetic acid. Silane is of practical interest as a precursor to elemental silicon. Sila ...
s.
It was once used for the industrial production of
freon
Freon ( ) is a registered trademark of the Chemours Company and generic descriptor for a number of halocarbon products. They are stable, nonflammable, low toxicity gases or liquids which have generally been used as refrigerants and as aerosol prope ...
. Other fluorine-containing
Lewis acids
A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any spe ...
serve as fluorinating agents in conjunction with
hydrogen fluoride.
SbF
3 is used in dyeing and in
pottery
Pottery is the process and the products of forming vessels and other objects with clay and other ceramic materials, which are fired at high temperatures to give them a hard and durable form. Major types include earthenware, stoneware and ...
, to make ceramic enamels and glazes.
Safety
The lethal minimum dose (guinea pig, oral) is 100 mg/kg.
[Sabina C. Grund, Kunibert Hanusch, Hans J. Breunig, Hans Uwe Wolf “Antimony and Antimony Compounds” in Ullmann's Encyclopedia of Industrial Chemistry 2006, Wiley-VCH, Weinheim. ]
References
External links
WebBook page for SbF3
{{DEFAULTSORT:Antimony Trifluoride
Antimony(III) compounds
Fluorides
Metal halides
Fluorinating agents