Phosphorus sesquisulfide is the

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 chemist ...

with the

formula In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwee ...

. It was developed by Henri Sevene and Emile David Cahen in 1898 as part of their invention of

friction match A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden matc ...

es that did not pose the health hazards of

white phosphorus Elemental phosphorus can exist in several allotropes, the most common of which are white and red solids. Solid violet and black allotropes are also known. Gaseous phosphorus exists as diphosphorus and atomic phosphorus. White phosphorus White ...

. This yellow solid is one of two commercially produced

phosphorus sulfide Phosphorus sulfides comprise a family of inorganic compounds containing only phosphorus and sulfur. These compounds have the formula with ''n'' ≤ 10. Two are of commercial significance, phosphorus pentasulfide (), which is made on a kiloton scale ...

s. It is a component of "strike anywhere" matches. Depending on purity, samples can appear yellow-green to grey. The compound was discovered by G. Lemoine and first produced safely in

commercial Commercial may refer to: * a dose of advertising conveyed through media (such as - for example - radio or television) ** Radio advertisement ** Television advertisement * (adjective for:) commerce, a system of voluntary exchange of products and s ...

quantities in 1898 by

Albright and Wilson Albright and Wilson was founded in 1856 as a United Kingdom manufacturer of potassium chlorate and white phosphorus for the match industry. For much of its first 100 years of existence, phosphorus-derived chemicals formed the majority of its produ ...

. It dissolves in an equal weight of

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 non ...

(), and in a 1:50 weight ratio of

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 atoms, ...

. Unlike some other phosphorus sulfides, is slow to hydrolyze and has a well-defined melting point.

Structure and synthesis

The molecule has C_3v

symmetry Symmetry (from grc, συμμετρία "agreement in dimensions, due proportion, arrangement") in everyday language refers to a sense of harmonious and beautiful proportion and balance. In mathematics, "symmetry" has a more precise definit ...

. It is a derivative of the tetrahedral () unit from insertion of sulfur into three P-P bonds. The P-S and P-P distances are 2.090 and 2.235 Å, respectively. and adopt the same structures. These compounds can be melted together and form mixed crystals of one dissolved in the other. Under higher temperatures, mixed chalcogenide molecules and will form. is produced by the reaction of red or white phosphorus with sulfur. Excess sulfur gives

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 d ...

(). It is estimated that 150 ton/y were produced in 1989.

Applications

and

potassium chlorate Potassium chlorate is a compound containing potassium, chlorine and oxygen, with the molecular formula KClO3. In its pure form, it is a white crystalline substance. After sodium chlorate, it is the second most common chlorate in industrial use. It ...

, together with other materials, composes the heads of "strike-anywhere

match A match is a tool for starting a fire. Typically, matches are made of small wooden sticks or stiff paper. One end is coated with a material that can be ignited by friction generated by striking the match against a suitable surface. Wooden matc ...

es".

Safety

Its flash point is about 100 °C.

Health effects

Exposure to "strike anywhere" matches containing phosphorus sesquisulfide can cause

contact dermatitis Contact dermatitis is a type of acute or chronic inflammation of the skin caused by exposure to chemical or physical agents. Symptoms of contact dermatitis can include itchy or dry skin, a red rash, bumps, blisters, or swelling. These rashes are ...

, usually in the pocket area but also on the face. Exposure over a long period of time to burning match tips (containing phosphorus sesquisulfide) can result in a recurring severe primary dermatitis about the eyes and face. Loosening of the teeth has also been reported which may have been due to phosphorus poisoning.

References

''This article contains public domain text from the NOAA as cited.'' {{Phosphorus compounds Inorganic phosphorus compounds Sulfides