Phosphorus sulfides comprise a family of

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as ''inorganic chemistr ...

s containing only

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ea ...

and

sulfur Sulfur (or sulphur in British English) is a chemical element with the symbol S and atomic number 16. It is abundant, multivalent and nonmetallic. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formul ...

. These compounds have the formula with ''n'' ≤ 10. Two are of commercial significance,

phosphorus pentasulfide Phosphorus pentasulfide is the inorganic compound with the formula (monomer) or (dimer). This yellow solid is the one of two phosphorus sulfides of commercial value. Samples often appear greenish-gray due to impurities. It is soluble in carbon ...

(), which is made on a kiloton scale for the production of other organosulfur compounds, and phosphorus sesquisulfide (), used in the production of "strike anywhere matches". There are several other phosphorus sulfides in addition to and . Six of these phosphorus sulfides exist as

isomer In chemistry, isomers are molecules or polyatomic ions with identical molecular formulae – that is, same number of atoms of each element – but distinct arrangements of atoms in space. Isomerism is existence or possibility of isomers. I ...

s: . These isomers are distinguished by Greek letter prefixes. The prefix is based on the order of the discovery of the isomers, not their structure. All known molecular phosphorus sulfides contain a tetrahedral array of four phosphorus atoms. is also known but is unstable above −30 °C.

Preparation

The main method for preparing these compounds is

thermolysis Thermal decomposition, or thermolysis, is a chemical decomposition caused by heat. The decomposition temperature of a substance is the temperature at which the substance chemically decomposes. The reaction is usually endothermic as heat is req ...

of mixtures of phosphorus and sulfur. The product distributions can be analyzed by ³¹P-NMR spectroscopy. More selective syntheses entail: *desulfurization, e.g. using

triphenylphosphine Triphenylphosphine (IUPAC name: triphenylphosphane) is a common organophosphorus compound with the formula P(C6H5)3 and often abbreviated to P Ph3 or Ph3P. It is widely used in the synthesis of organic and organometallic compounds. PPh3 exists a ...

and, complementarily, *sulfidation using

triphenylarsine Triphenylarsine is the chemical compound with the formula As(C6H5)3. This organoarsenic compound, often abbreviated As Ph3, is a colorless crystalline solid that is used as a ligand and a reagent in coordination chemistry and organic synthesis. The ...

sulfide.

Phosphorus sesquisulfide is prepared by treating red phosphorus with sulfur above 450 K, followed by careful recrystallization with

carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical n ...

and

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen a ...

. An alternative method involves the controlled fusion of white phosphorus with sulfur in an inert, non-flammable solvent.

The α- and β- forms of can be prepared by treating the corresponding isomers of with : Preparation scheme of P4S4 isomeric forms

can be synthesized by the reaction of stoichiometric amounts of phosphorus, sulfur, and iodine.

can be prepared by treating stoichiometric amounts of with sulfur in carbon disulfide solution, in the presence of light and a catalytic amount of

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vio ...

. The respective product distribution is then analyzed by using ³¹P-NMR spectroscopy. In particular, α- can be easily made by the

photochemical reaction Organic photochemistry encompasses organic reactions that are induced by the action of light. The absorption of ultraviolet light by organic molecules often leads to reactions. In the earliest days, sunlight was employed, while in more modern times ...

of with red phosphorus. Note that is unstable when heated, tending to disproportionate to and before reaching its melting point.

can be made by abstracting a sulfur atom from using

: : Treating α- with in also yields α-. The two new polymorphs δ- and ε- can be made by treating α- with in .

is most conveniently made by direct union of the corresponding elements, and is one of the most easily purified binary phosphorus sulfides. :

β- can be made by treating α- with in , which yields a mixture between α- and β-.

can be made by two methods. One method involves the heating of in excess sulfur. Another method involves the heating of and in 1:2 mole ratio, where is reversibly formed: :

is one of the most stable phosphorus sulfides. It is most easily made by heating white phosphorus with sulfur above 570 K in an evacuated tube."Diphosphorus pentasulfide" in Handbook of Preparative Inorganic Chemistry, 2nd Ed. Edited by G. Brauer, Academic Press, 1963, NY. Vol. 1. p. 567. :

References

{{Sulfides Inorganic phosphorus compounds Sulfides

Preparation

See also

References