Antimony pentasulfide

Antimony pentasulfide is an inorganic compound of antimony and sulfur, also known as antimony red. It is a nonstoichiometric compound with a variable composition. Its exact structure is unknown.[2] Commercial samples are usually contaminated with sulfur, which may be removed by washing with carbon disulfide in a Soxhlet extractor.

Antimony pentasulfide

Identifiers
CAS Number	1315-04-4
3D model (JSmol)	Interactive image
ChEBI	CHEBI:134733
ChemSpider	17615643
ECHA InfoCard	100.013.869
EC Number	215-255-5
PubChem CID	16683083
UNII	1433F1I86N
CompTox Dashboard (EPA)	DTXSID8046583
InChI InChI=1S/5S.2Sb Key: PPKVREKQVQREQD-UHFFFAOYSA-N
SMILES S=[Sb](=S)S[Sb](=S)=S
Properties
Chemical formula	S5Sb2
Molar mass	403.82 g·mol^−1
Appearance	yellow to orange powder
Density	4.12 g/cm ^3
Melting point	135 °C (275 °F; 408 K) (decomposes)
Solubility in water	insoluble
Solubility	soluble in HCl soluble in alkalis
Pharmacology
ATC code	R05CA07 (WHO)
Hazards
GHS pictograms
GHS Signal word	Warning
GHS hazard statements	H228, H302, H332, H411
GHS precautionary statements	P210, P240, P241, P261, P264, P270, P271, P273, P280, P301+312, P304+312, P304+340, P312, P330, P370+378, P391, P501
Flash point	flammable
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.5 mg/m^3 (as Sb)[1]
REL (Recommended)	TWA 0.5 mg/m^3 (as Sb)[1]
Related compounds
Related compounds	Antimony(III) sulfide
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

Production

Antimony pentasulfide can be produced by the reaction of antimony with sulfur at a temperature between 250-400 °C in an inert atmosphere.

Uses

It may be used as a red pigment and is one possible precursor to Schlippe's Salt, Na₃SbS₄, which can be prepared according to the equation:

3 Na₂S   +   Sb₂S₅   +   9 H₂O   →   2 Na₃SbS₄·9H₂O

Physical chemistry

Like many sulfides, this compound liberates hydrogen sulfide upon treatment with strong acids like hydrochloric acid.[3]

6 HCl   +   Sb₂S₅   →   2 SbCl₃   +   3 H₂S   +   2 S

Analysis by Mössbauer spectroscopy indicates that this compound is a derivative antimony(III),[4] explaining the production of antimony(III) chloride, rather than antimony(V) chloride, upon acidification. It is therefore not analogous to the phosphorus(V) compound phosphorus pentasulfide.

References

1. NIOSH Pocket Guide to Chemical Hazards. "#0036". National Institute for Occupational Safety and Health (NIOSH).
2. Arnold F. Holleman, Nils Wiberg: Lehrbuch der Anorganischen Chemie, 102nd edition, de Gruyter, Berlin 2007, p. 849, ISBN 978-3-11-017770-1.
3. Strem MSDS
4. G. G. Long; J. G. Stevens; L. H. Bowen; S. L. Ruby (1969). "The oxidation number of antimony in antimony pentasulfide". Inorganic and Nuclear Chemistry Letters. 5 (1): 21–25. doi:10.1016/0020-1650(69)80231-X.