Phosphorus pentasulfide

Structure and synthesis

Its tetrahedral molecular structure is similar to that of adamantane and almost identical to the structure of phosphorus pentoxide.

Phosphorus pentasulfide is obtained by the reaction of liquid white phosphorus () with sulfur above 300 °C. The first synthesis of by Berzelius in 1843 was by this method. Alternatively, can be formed by reacting elemental sulfur or pyrite, , with ferrophosphorus, a crude form of (a byproduct of white phosphorus () production from phosphate rock): : :

Applications

Approximately 150,000 tons of are produced annually. The compound is mainly converted to other derivatives for use as lubrication additives such as zinc dithiophosphates. It is widely used in the production of sodium dithiophosphate for applications as a flotation agent in the concentration of molybdenite minerals. 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. -) for some types of lithium batteries.

Phosphorus pentasulfide is a dual-use material, for the production of early insecticides such as Amiton and also for the manufacture of the related VX nerve agents.

Phosphorus pentasulfide reacts with ethanol to give diethyl dithiophosphoric acid: : Diorganodithiophosphoric acids are used to produce metal dithiophosphates, which are used commercially.

Reactivity

Due to hydrolysis by atmospheric moisture, evolves hydrogen sulfide , thus is associated with a rotten egg odour. Aside from , hydrolysis of eventually gives phosphoric acid: : Other mild nucleophiles react with , including alcohols and amines. Reaction with ammonium chloride gives the polymeric (SPN)∞. 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: : (Ar = aryl)

Thionations

is used as a reagent for thionation (thiation). In doing so, P=S bonds are converted to P=O bonds, concomitant with C=O bonds converting to C=S. Some ketones, esters, and imides are converted to the corresponding thiocarbonyls. Amides give thioamides. With 1,4-diketones the reagent forms thiophenes. is also used to deoxygenate sulfoxides. Typical conditions entail boiling organic solvents (benzene, dioxane, or acetonitrile). Hexamethyldisiloxane is an effective solvent for these thionations because the phosphorus-containing side products are more easily separated from the products.

The use of has been displaced somewhat by the aforementioned Lawesson's reagent.

It is probable that thionation reactions involve dissociation of into more reactive species, perhaps . Supporting evidence is the reaction of with pyridine to form the complex .

References

References

1. {{PGCH. 0510
2. {{IDLH. 1314803. Phosphorus pentasulfide
3. Scott D. Edmondson, Mousumi Sannigrahi "Phosphorus(V) sulfide" Encyclopedia of Reagents for Organic Synthesis 2004 John Wiley & Sons. {{doi. 10.1002/047084289X.rp166s.pub2
4. Corbridge, D. E. C.. (1995). "Phosphorus: An Outline of its Chemistry, Biochemistry, and Technology". Elsevier.
5. Berzelius, Jons J. (1843). "Ueber die Verbindungen des Phosphors mit Schwefel", parts [https://zenodo.org/record/1426971 I] and [https://zenodo.org/record/1426973 II]. ''Annalen der Chemie und Pharmacie'', vol. 46, issue 2, pp. 129–154, 251–281. {{doi. 10.1002/jlac.18430460202 and [https://dx.doi.org/10.1002/jlac.18430460303 10.1002/jlac.18430460303].
6. {{ cite encyclopedia. (2002). Wiley-VCH
7. (1960). "Inorganic Syntheses".
8. Almasi, Lucreţia. (1971). "Sulfur in Organic and Inorganic Chemistry". Marcel Dekker.
9. Spencer Knapp, Richard A. Huhn, Benjamin Amorelli. (2007). "Thionation: GlcNAc-Thiazoline Triacetate". Organic Syntheses.
10. (2010). "A Berzelius Reagent, Phosphorus Decasulfide (P₄S₁₀), in Organic Syntheses". Chemical Reviews.
11. (2011). "Thionations Using a P4S10−Pyridine Complex in Solvents Such as Acetonitrile and Dimethyl Sulfone". The Journal of Organic Chemistry.