|Molar mass||444.555 g mol|
|Melting point||288 °C (561 K)|
|Boiling point||514 °C (787 K)|
|Solubility in water||hydrolyses|
|Solubility in other solvents||0.222 g / 100g CS2 (at 17 °C)
Insoluble in C6H6
Insoluble in hot xylene
Insoluble in hot anisole.
|Crystal structure||triclinic, aP28|
|Space group||P-1, No. 2|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Phosphorus pentasulfide is the inorganic compound with the formula P4S10. This yellow solid is the one of two phosphorus sulfides of commercial value. Samples often appear greenish-gray due to impurities.
Structure and synthesis
Phosphorus pentasulfide is obtained by the reaction of liquid white phosphorus (P4) with sulfur above 300 °C. The first synthesis of P4S10 by Berzelius in 1843  was by this method. Alternatively, P4S10 can be formed by reacting elemental sulfur or pyrite, FeS2, with ferrophosphorus, a crude form of Fe2P (a byproduct of P4 production from phosphate rock):
- 4 Fe2P + 18 S → P4S10 + 8 FeS
- 4 Fe2P + 18 FeS2 + heat → P4S10 + 26 FeS
Approximately 150,000 tons of P4S10 are produced annually. The compound is mainly converted to other derivatives for use as lubrication additives such zinc dithiophosphates. It is also used in the production of pesticides such as Parathion and Malathion. It is also a component of some amorphous solid electrolytes (e.g. Li2S-P2S5) for some types of lithium batteries.
- P4S10 + 16 H2O → 4 H3PO4 + 10 H2S
Other mild nucleophiles react with P4S10, including alcohols and amines. Aromatic compounds such as anisole, ferrocene and 1-methoxynaphthalene react to form 1,3,2,4-dithiadiphosphetane 2,4-disulfides such as Lawesson's reagent.
In organic chemistry P4S10 is used as a thionation reagent. Reactions of this type require refluxing solvents such as benzene, dioxane or acetonitrile with P4S10 dissociating into P2S5. P2S5 can be trapped for example as the pyridine complex. Ketones are converted to thioketones. In esters, imides and lactones the oxygen atom can also be replaced by sulfur. With amides the reaction product is a thioamide. With 1,4-diketones the reagent forms a thiophene. Compared to the better known Lawesson's reagent P4S10 suffers from reduced yields.
- Corbridge, D. E. C. (1995). Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology (5th ed.). Amsterdam: Elsevier. ISBN 0-444-89307-5.
- Berzelius, J. (1843). "Ueber die Verbindungen des Phosphors mit Schwefel". Annalen der Chemie und Pharmacie 46 (2): 129–154. doi:10.1002/jlac.18430460202.
- Berzelius, J. (1843). "Ueber die Verbindungen des Phosphors mit Schwefel". Annalen der Chemie und Pharmacie 46 (3): 251–281. doi:10.1002/jlac.18430460303. (continuation of p. 154 of the same volume)
- Bettermann, G.; Krause, W.; Riess, G.; Hofmann, T. (2002). "Phosphorus Compounds, Inorganic". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_527.
- Ozturk, T.; Ertas, E.; Mert, O. (2010). "A Berzelius Reagent, Phosphorus Decasulfide (P4S10), in Organic Syntheses". Chemical Reviews 110 (6): 3419–3478. doi:10.1021/cr900243d. PMID 20429553.