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


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.


  1. ^ a b 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.