Antimony trichloride

Antimony 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.

Antimony trichloride

Stereo structural formula of antimony trichloride Ball and stick model of antimony trichloride
Names
Preferred IUPAC name Antimony trichloride
Systematic IUPAC name Trichlorostibane
Other names Antimony(III) chloride, Butter of antimony, Antimonous chloride, Stibous chloride, Trichlorostibine
Identifiers
CAS Number	10025-91-9
3D model (JSmol)	Interactive image
ChEBI	CHEBI:74856
ChemSpider	23199
ECHA InfoCard	100.030.031
EC Number	233-047-2
KEGG	C15235
MeSH	Antimony+trichloride
PubChem CID	24814
RTECS number	CC4900000
UNII	J281401KK3
UN number	1733
CompTox Dashboard (EPA)	DTXSID4044161
InChI InChI=1S/3ClH.Sb/h3*1H;/q;;;+3/p-3 Key: FAPDDOBMIUGHIN-UHFFFAOYSA-K InChI=1S/3ClH.Sb/h3*1H;/q;;;+3/p-3 Key: FAPDDOBMIUGHIN-UHFFFAOYSA-K InChI=1/3ClH.Sb/h3*1H;/q;;;+3/p-3 Key: FAPDDOBMIUGHIN-DFZHHIFOAK
SMILES Cl[Sb](Cl)Cl
Properties
Chemical formula	Cl3Sb
Molar mass	228.11 g·mol^−1
Appearance	Colorless solid, very hygroscopic
Odor	Sharp, pungent
Density	3.14 g/cm^3 (25 °C) 2.51 g/cm^3 (150 °C)[1]
Melting point	73.4 °C (164.1 °F; 346.5 K) [2]
Boiling point	223.5 °C (434.3 °F; 496.6 K)
Solubility in water	601.1 g/100 mL (0 °C)[1] 985.1 g/100 mL (25 °C) 1.357 kg/100 mL (40 °C)[3]
Solubility	Soluble in acetone, ethanol, CH2Cl2, phenyls, ether, dioxane, CS2, CCl4, CHCl3, cyclohexane, selenium(IV) oxychloride Insoluble in pyridine, quinoline, organic bases
Solubility in acetic acid	143.9 g/100 g (0 °C) 205.8 g/100 g (10 °C) 440.5 g/100 g (25 °C)[4] 693.7 g/100 g (45 °C)[3]
Solubility in acetone	537.6 g/100 g (18 °C)[3][4]
Solubility in benzoyl chloride	139.2 g/100 g (15 °C) 169.5 g/100 g (25 °C)[4] 2.76 kg/100 g (70 °C)[3]
Solubility in hydrochloric acid	20 °C: 8.954 g/ g (4.63% w/w) 8.576 g/ g (14.4% w/w) 7.898 g/ g (36.7% w/w)[3]
Solubility in p-Cymene	69.5 g/100 g (-3.5 °C) 85.5 g/100 g (10 °C) 150 g/100 g (30 °C) 2.17 kg/100 g (70 °C)[3]
Vapor pressure	13.33 Pa (18.1 °C)[4] 0.15 kPa (50 °C) 2.6 kPa (100 °C)[5]
Magnetic susceptibility (χ)	-86.7·10^−6 cm^3/mol
Refractive index (nD)	1.46[1]
Structure
Crystal structure	Orthorhombic
Dipole moment	3.93 D (20 °C)[4]
Thermochemistry
Heat capacity (C)	183.3 J/mol·K[4]
Std molar entropy (S^o298)	110.5 J/mol·K[4]
Std enthalpy of formation (ΔfH^⦵298)	-381.2 kJ/mol[4]
Gibbs free energy (ΔfG˚)	-322.5 kJ/mol[4]
Hazards
Safety data sheet	ICSC 1224
GHS pictograms	[2]
GHS Signal word	Danger
GHS hazard statements	H314, H411[2]
GHS precautionary statements	P273, P280, P305+351+338, P310[2]
NFPA 704 (fire diamond)	0 2 1
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	525 mg/kg (oral, rat)
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.5 mg/m^3 (as Sb)[6]
REL (Recommended)	TWA 0.5 mg/m^3 (as Sb)[6]
Related compounds
Other anions	Antimony trifluoride Antimony tribromide Antimony triiodide
Other cations	Nitrogen trichloride Phosphorus trichloride Arsenic trichloride Bismuth chloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Preparation

Antimony trichloride is prepared by reaction of chlorine with antimony, antimony tribromide, antimony trioxide, or antimony trisulfide. It also may be made by treating antimony trioxide with concentrated hydrochloric acid.

Reactions

Antimony trichloride solution in hydrochloric acid

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:

SbCl₃ + H₂O → SbOCl + 2 HCl

With more water it forms Sb₄O₅Cl₂ which on heating to 460° under argon converts to Sb₈O₁₁Cl₁₂.[7]

SbCl₃ readily forms complexes with halides, but the stoichiometries are not a good guide to the composition,[7] for example the (C₅H₅NH)SbCl₄ contains a chain anion with distorted Sb^III octahedra. Similarly the salt (C₄H₉NH₃)₂SbCl₅ contains a polymeric anion of composition [SbCl₅²⁻]_n with distorted octahedral Sb^III.[8]

With nitrogen donor ligands, L, complexes with a stereochemically active lone-pair are formed, for example Ψ-trigonal bipyramidal LSbCl₃ and Ψ-octahedral L₂SbCl₃.[9]

SbCl₃ is only a weak Lewis base,[7] however some complexes are known for example the carbonyl complexes, Fe(CO)₃(SbCl₃)₂ and Ni(CO)₃SbCl₃.[9]

Structure

In the gas phase SbCl₃ is pyramidal with a Cl-Sb-Cl angle of 97.2° and a bond length of 233 pm.[10] 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.[10][7]

Uses

SbCl₃ is a reagent for detecting vitamin A and related carotenoids in the Carr-Price test. The antimony trichloride reacts with the carotenoid to form a blue complex that can be measured by colorimetry.

Antimony trichloride has also been used as an adulterant to enhance the louche effect in absinthe. 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; and in the production of other antimony salts. Its solution is used as an analytical reagent for chloral, aromatics, and vitamin A.[11] It has a very potential use as a Lewis acid catalyst in synthetic organic transformation.

A solution of antimony trichloride in liquid hydrogen sulfide 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.[12]

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), several calves died following an episode of nonspecific gastroenteritis, the cause of which was later determined to be ingestion of antimony trichloride present in a solution used to dissolve their horn stubs.

References

1. "Antimony Trichloride, SbCl3".
2. Sigma-Aldrich Co., Antimony(III) chloride. Retrieved on 2014-05-29.
3. Seidell, Atherton; Linke, William F. (1952). Solubilities of Inorganic and Organic Compounds. Van Nostrand.
4. "Antimony(III) chloride".
5. Antimony trichloride in Linstrom, Peter J.; Mallard, William G. (eds.); NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg (MD), http://webbook.nist.gov (retrieved 2014-05-28)
6. NIOSH Pocket Guide to Chemical Hazards. "#0036". National Institute for Occupational Safety and Health (NIOSH).
7. Greenwood, Norman N.; Earnshaw, Alan (1984). Chemistry of the Elements. Oxford: Pergamon Press. pp. 558–571. ISBN 978-0-08-022057-4.
8. Zarychta, B.; Zaleski, J. "Phase transitions mechanism and distortion of SbCl₆³⁻ octahedra in bis(n-butylammonium) pentachloroantimonate(III) (C₄H₉NH₃)₂[SbCl₅]". Z. Naturforsch. B 2006, 61, 1101–1109. Abstract (PDF)
9. "Antimony: Inorganic Chemistry" R. Bruce King Encyclopedia of Inorganic Chemistry Editor R Bruce King (1994) John Wiley and Sons ISBN 0-471-93620-0
10. Wells A.F. (1984) Structural Inorganic Chemistry 5th edition, pp. 879 - 884, Oxford Science Publications, ISBN 0-19-855370-6
11. Patnaik, P. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8.
12. Wilkinson, John A. (1931). "Liquid Hydrogen Sulfide as a Reaction Medium". Chemical Reviews. 8 (2): 237–250. doi:10.1021/cr60030a005. ISSN 0009-2665.

External links