Antimony pentachloride

Antimony pentachloride is a chemical compound with the formula SbCl5. It is a colourless oil, but typical samples are yellowish due to impurities. Owing to its tendency to hydrolyse to hydrochloric acid, SbCl5 is a highly corrosive substance and must be stored in glass or PTFE containers.

Antimony pentachloride
Antimony pentachloride
Names
IUPAC names
Antimony pentachloride
Antimony(V) chloride
Other names
Antimonic chloride
Antimony perchloride
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.028.729
EC Number
  • 231-601-8
RTECS number
  • CC5075000
UNII
Properties
Cl5Sb
Molar mass 299.01 g·mol−1
Appearance colorless or reddish-yellow (fuming) liquid, oily
Odor pungent, offensive
Density 2.336 g/cm3 (20 °C)[1]
2.36 g/cm3 (25 °C)[2]
Melting point 2.8 °C (37.0 °F; 275.9 K)
Boiling point 140 °C (284 °F; 413 K)
decomposes from 106 °C[3]
79 °C (174 °F; 352 K)
at 22 mmHg[1]
92 °C (198 °F; 365 K)
at 30 mmHg[2]
reacts
Solubility soluble in alcohol, HCl, tartaric acid, CHCl3, CS2, CCl4
Solubility in selenium(IV) oxychloride 62.97 g/100 g (25 °C)
Vapor pressure 0.16 kPa (25 °C)
4 kPa (40 °C)
7.7 kPa (100 °C)[4]
-120.0·10−6 cm3/mol
1.59255
Viscosity 2.034 cP (29.4 °C)[1]
1.91 cP (35 °C)
Structure
Trigonal bipyramidal
0 D
Thermochemistry
120.9 J/mol·K (gas)[3]
295 J/mol·K[3]
-437.2 kJ/mol[3]
-345.35 kJ/mol[3]
Hazards
GHS pictograms [2]
GHS Signal word Danger
H314, H411[2]
P273, P280, P305+351+338, P310[2]
Inhalation hazard Toxic
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasReactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazard W: Reacts with water in an unusual or dangerous manner. E.g. sodium, sulfuric acid
0
3
1
Flash point 77 °C (171 °F; 350 K)
Lethal dose or concentration (LD, LC):
1115 mg/kg, (rat, oral)[3]
NIOSH (US health exposure limits):
PEL (Permissible)
TWA 0.5 mg/m3 (as Sb)[5]
REL (Recommended)
TWA 0.5 mg/m3 (as Sb)[5]
Related compounds
Other anions
Antimony pentafluoride
Other cations
Phosphorus pentachloride
Related compounds
Antimony trichloride
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

Preparation and structure

Antimony pentachloride is prepared by passing chlorine gas into molten antimony trichloride:

SbCl3 + Cl2 → SbCl5

Gaseous SbCl5 has a trigonal bipyramidal structure.[6]

Reactions

Antimony pentachloride hydrolyses to give hydrochloric acid and antimony oxychlorides. This reaction is suppressed in the presence of a large excess of chloride, owing to the formation of the hexachloroantimonate complex ion:

SbCl5 + Cl → [SbCl6]

The mono- and tetrahydrates are known, SbCl5·H2O and SbCl5·4H2O.

This compound forms adducts with many Lewis bases. SbCl5 is a soft Lewis acid and its ECW model parameters are EA = 3.64 and CA = 10.42. It is used as the standard Lewis acid in the Gutmann scale of Lewis basicity.[7] However, Cramer-Bopp plots show that a one-parameter basicity scale is incomplete and that there is no single rank order of base strength. These plots show that to define the order of Lewis base strength (or Lewis acid strength) at least two properties must be considered.[8][9]

It is also a strong oxidizing agent.[10]

Applications

Antimony pentachloride is used as a polymerization catalyst and for the chlorination of organic compounds.

Precautions

Antimony pentachloride is a highly corrosive substance that should be stored away from heat and moisture. It is a chlorinating agent and, in the presence of moisture, it releases hydrogen chloride gas. Because of this, it may etch even stainless-steel tools (such as needles), if handled in a moist atmosphere. It should not be handled with non-fluorinated plastics (such as plastic syringes, plastic septa, or needles with plastic fittings), since it melts and carbonizes plastic materials.[11]

References

  1. "Antimony pentachloride (UK PID)".
  2. Sigma-Aldrich Co., Antimony(V) chloride. Retrieved on 2014-05-29.
  3. "Antimony(V) chloride".
  4. Antimony pentachloride 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 2014-05-29)
  5. NIOSH Pocket Guide to Chemical Hazards. "#0036". National Institute for Occupational Safety and Health (NIOSH).
  6. Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  7. V. Gutmann (1976). "Solvent effects on the reactivities of organometallic compounds". Coord. Chem. Rev. 18 (2): 225–255. doi:10.1016/S0010-8545(00)82045-7.
  8. Laurence, C. and Gal, J.-F. Lewis Basicity and Affinity Scales, Data and Measurement, (Wiley 2010) pp 50-51 IBSN 978-0-470-74957-9
  9. Cramer, R. E.; Bopp, T. T. (1977). "Graphical display of the enthalpies of adduct formation for Lewis acids and bases". Journal of Chemical Education. 54: 612–613. doi:10.1021/ed054p612. The plots shown in this paper used older parameters. Improved E&C parameters are listed in ECW model.
  10. Connelly, N. G.; Geiger, W. E. (1996). "Chemical Redox Agents for Organometallic Chemistry". Chem. Rev. 96 (2): 877–922. doi:10.1021/cr940053x. PMID 11848774.
  11. Shekarchi, M.; Behbahani, F. K Catal. Lett. 2017 147 2950. doi:10.1007/s10562-017-2194-2
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