Antimony trichloride is the

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 the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...

SbCl₃. It is a soft colorless solid with a pungent odor and was known to

alchemists Alchemy (from Arabic: ''al-kīmiyā''; from Ancient Greek: χυμεία, ''khumeía'') is an ancient branch of natural philosophy, a philosophical and protoscientific tradition that was historically practiced in China, India, the Muslim ...

as butter of antimony.

Preparation

Antimony trichloride is prepared by reaction of

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 ...

with

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 ti ...

antimony tribromide Antimony tribromide ( Sb Br3) is a chemical compound containing antimony in its +3 oxidation state. Production It may be made by the reaction of antimony with elemental bromine, or by the reaction of antimony trioxide with hydrobromic acid. Al ...

antimony trioxide Antimony(III) oxide is the inorganic compound with the formula Sb2O3. It is the most important commercial compound of antimony. It is found in nature as the minerals valentinite and senarmontite. Like most polymeric oxides, Sb2O3 dissolves i ...

, or

antimony trisulfide Antimony trisulfide (Sb2S3) is found in nature as the crystalline mineral stibnite and the amorphous red mineral (actually a mineraloid) metastibnite. It is manufactured for use in safety matches, military ammunition, explosives and fireworks. It ...

. It also may be made by treating antimony trioxide with concentrated

hydrochloric acid Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride. It is a colorless solution with a distinctive pungent smell. It is classified as a strong acid. It is a component of the gastric acid in the dige ...

Reactions

SbCl₃ is readily hydrolysed and samples of SbCl₃ must be protected from moisture. With a limited amount of water it forms antimony oxychloride releasing

hydrogen chloride The compound hydrogen chloride has the chemical formula and as such is a hydrogen halide. At room temperature, it is a colourless gas, which forms white fumes of hydrochloric acid upon contact with atmospheric water vapor. Hydrogen chlorid ...

: :SbCl₃ + H₂O → SbOCl + 2 HCl With more water it forms which on heating to 460° under argon converts to . SbCl₃ readily forms complexes with halides, but the stoichiometries are not a good guide to the composition, for example the contains a chain anion with distorted Sb^III octahedra. Similarly the salt contains a polymeric anion of composition with distorted octahedral Sb^III. With nitrogen donor ligands, L, complexes with a stereochemically active lone-pair are formed, for example Ψ-trigonal bipyramidal LSbCl₃ and Ψ-octahedral ."Antimony: Inorganic Chemistry" R. Bruce King ''Encyclopedia of Inorganic Chemistry'' Editor R Bruce King (1994) John Wiley and Sons SbCl₃ is only a weak Lewis base, however some complexes are known for example the

carbonyl complex Metal carbonyls are coordination complexes of transition metals with carbon monoxide ligands. Metal carbonyls are useful in organic synthesis and as catalysts or catalyst precursors in homogeneous catalysis, such as hydroformylation and Reppe ch ...

es, and .

Structure

In the gas phase SbCl₃ is pyramidal with a Cl-Sb-Cl angle of 97.2° and a bond length of 233 pm. Wells A.F. (1984) ''Structural Inorganic Chemistry'' 5th edition, pp. 879 - 884, Oxford Science Publications, In SbCl₃ each Sb has three Cl atoms at 234 pm showing the persistence of the molecular SbCl₃ unit, however there are a further five neighboring Cl atoms, two at 346 pm, one at 361 pm, and two at 374 pm. These eight atoms can be considered as forming a bicapped trigonal prism. These distances can be contrasted with BiCl₃ which has three near neighbors at 250 pm, with two at 324 pm, and three at a mean of 336 pm. The point to note here is that the all eight close neighbours of Bi are closer than the eight closest neighbours of Sb, demonstrating the tendency for Bi to adopt higher coordination numbers.

Uses

SbCl₃ is a

reagent In chemistry, a reagent ( ) or analytical reagent is a substance or compound added to a system to cause a chemical reaction, or test if one occurs. The terms ''reactant'' and ''reagent'' are often used interchangeably, but reactant specifies a ...

for detecting

vitamin A Vitamin A is a fat-soluble vitamin and an essential nutrient for humans. It is a group of organic compounds that includes retinol, retinal (also known as retinaldehyde), retinoic acid, and several provitamin A carotenoids (most notably ...

and related

carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic pigments that are produced by plants and algae, as well as several bacteria, and fungi. Carotenoids give the characteristic color to pumpkins, carrots, parsnips, ...

s in the Carr-Price test. The antimony trichloride reacts with the carotenoid to form a blue

complex Complex commonly refers to: * Complexity, the behaviour of a system whose components interact in multiple ways so possible interactions are difficult to describe ** Complex system, a system composed of many components which may interact with each ...

that can be measured by

colorimetry Colorimetry is "the science and technology used to quantify and describe physically the human color perception". It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color ...

. Antimony trichloride has also been used as an

adulterant An adulterant is caused by the act of adulteration, a practice of secretly mixing a substance with another. Typical substances that are adulterated include but are not limited to food, cosmetics, pharmaceuticals, fuel, or other chemicals, that ...

to enhance the louche effect in

absinthe Absinthe (, ) is an anise-flavoured spirit derived from several plants, including the flowers and leaves of '' Artemisia absinthium'' ("grand wormwood"), together with green anise, sweet fennel, and other medicinal and culinary herbs. Historica ...

. It has been used in the past to dissolve and remove horn stubs from calves without having to cut them off. It is also used as a catalyst for polymerization, hydrocracking, and chlorination reactions; as a

mordant A mordant or dye fixative is a substance used to set (i.e. bind) dyes on fabrics by forming a coordination complex with the dye, which then attaches to the fabric (or tissue). It may be used for dyeing fabrics or for intensifying stains in ...

; and in the production of other antimony salts. Its solution is used as an analytical reagent for chloral, aromatics, and

. It has a very potential use as a Lewis acid catalyst in synthetic organic transformation. A solution of antimony trichloride in liquid

hydrogen sulfide Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The under ...

is a good conductor, though the applications of such are limited by the very low temperature or high pressure required for hydrogen sulfide to be liquid.

References in popular culture

In episode 12 of the third season of the popular British program '' All Creatures Great and Small'' (adapted from chapter six of the book ''

All Things Wise and Wonderful James Alfred Wight (3 October 1916 – 23 February 1995), better known by his pen name James Herriot, was a British veterinary surgeon and author. Born in Sunderland, Wight graduated from Glasgow Veterinary College in 1939, returning to En ...

''), several calves died following an episode of nonspecific

gastroenteritis Gastroenteritis, also known as infectious diarrhea and gastro, is an inflammation of the gastrointestinal tract including the stomach and intestine. Symptoms may include diarrhea, vomiting, and abdominal pain. Fever, lack of energy, and dehydr ...

, the cause of which was later determined to be ingestion of antimony trichloride present in a solution used to dissolve their horn stubs.

References

{{Chlorides Chlorides Metal halides Antimony(III) compounds Alchemical substances