chemistry

Phosphorus sesquisulfide

Phosphorus sesquisulfide is a chemistry topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Phosphorus sesquisulfide rather than just read about it. In short: Phosphorus sesquisulfide is the inorganic compound with the formula P4S3. It was developed by Henri Sevene and Emile David Cahen in 1898 as part of their invention of friction matches that did not pose the health hazards of white phosphorus.

Key takeaways

Phosphorus sesquisulfide belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Phosphorus sesquisulfide to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Phosphorus sesquisulfide from memory before moving on to harder problems.

Reference excerpt

Phosphorus sesquisulfide is the inorganic compound with the formula P4S3. It was developed by Henri Sevene and Emile David Cahen in 1898 as part of their invention of friction matches that did not pose the health hazards of white phosphorus. This yellow solid is one of two commercially produced phosphorus sulfides. 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 quantities in 1898 by Albright and Wilson. It dissolves in an equal weight of carbon disulfide (CS2), and in a 1:50 weight ratio of benzene. Unlike some other phosphorus sulfides, P4S3 is slow to hydrolyze and has a well-defined melting point.

Structure and synthesis The molecule has C3v symmetry. It is a derivative of the tetrahedral (P4) 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. P4Se3 and P4S3 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 P4S2Se and P4SSe2 will form. P4S3 is produced by the reaction of red or white phosphorus with sulfur. Excess sulfur gives phosphorus pentasulfide (P4S10). It is estimated that 150 ton/y were produced in 1989.

Applications P4S3 and potassium chlorate, together with other materials, composes the heads of "strike-anywhere matches".

Safety Its flash point is about 100 °C.

Health effects Exposure to "strike anywhere" matches containing phosphorus sesquisulfide can cause contact dermatitis, 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.

Illustrations

Worked examples

Example 1 — a first encounter with Phosphorus sesquisulfide

Start with the simplest possible case. Write down what Phosphorus sesquisulfide claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Phosphorus sesquisulfide before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Phosphorus sesquisulfide ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Phosphorus sesquisulfide

In research: Phosphorus sesquisulfide appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Phosphorus sesquisulfide in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Phosphorus sesquisulfide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Inorganic phosphorus compounds, Phosphorus(I) compounds, Phosphorus(III) compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Phosphorus sesquisulfide outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Phosphorus sesquisulfide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Phosphorus sesquisulfide means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Phosphorus sesquisulfide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Phosphorus sesquisulfide in simple terms?

Why does Phosphorus sesquisulfide matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Phosphorus sesquisulfide?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Phosphorus sesquisulfide.