chemistry

Lanthanum phosphide

Lanthanum phosphide 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 Lanthanum phosphide rather than just read about it. In short: Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP. Synthesis Lanthanum phosphide can be made by heating lanthanum metal with excess phosphorus in a vacuum: 4 La + P4 → 4 LaP Physical properties Lanthanum phosphide forms black crystals of a cubic system, space group Fm3m, cell parameters a = 0.6025 nm, with number of formulas per unit cell Z = 4.

Key takeaways

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

Reference excerpt

Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP.

Synthesis Lanthanum phosphide can be made by heating lanthanum metal with excess phosphorus in a vacuum:

4 La + P4 → 4 LaP

Physical properties Lanthanum phosphide forms black crystals of a cubic system, space group Fm3m, cell parameters a = 0.6025 nm, with number of formulas per unit cell Z = 4. The crystals are very unstable and decompose in the open air.

Electronic properties Lanthanum phosphide is an example of a strongly correlated material, complicating theoretical prediction of its properties. According to HSE06 calculations, lanthanum phosphide has been theoretically predicted to have an indirect band gap of 0.25 eV along the Γ-X direction. According to HSE06 calculations with spin-orbit coupling, the band gap is predicted to be a direct gap of 0.72 eV at the X point. Using EVGGA, the compound is predicted to have a band gap of 0.56 eV along the Γ-X direction. FP-LAPW has predicted an indirect gap of 0.33 eV along the Γ-X direction.

Chemical properties Lanthanum phosphide reacts with water, releasing highly toxic phosphine gas:

LaP + 3H2O → La(OH)3 + PH3

Uses Lanthanum phosphide is a semiconductor used in high power, high frequency applications, and in laser diodes.

Lanthanum polyphosphide In addition to the simple phosphide, LaP, lanthanum and phosphorus can also form phosphorus-rich compounds such as LaP2 LaP5 and LaP7.

References

Further reading Iandelli, A.; Botti, R. (1936). "On the crystal structure of compounds of the rare earths with metalloids of the V group. Phosphides of La, Ce, Pr". Rendiconti Lincei. VI. 24. Accademia dei Lincei: 459. ISSN 0001-4435. OCLC 8450083. HathiTrust (no access)

Illustrations

Worked examples

Example 1 — a first encounter with Lanthanum phosphide

Start with the simplest possible case. Write down what Lanthanum phosphide 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 Lanthanum phosphide 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 Lanthanum phosphide 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 Lanthanum phosphide

In research: Lanthanum phosphide 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 Lanthanum phosphide 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: Lanthanum phosphide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Lanthanum compounds, Phosphides, Rock salt crystal structure, so understanding it makes those chapters shorter.
In everyday life: Look for Lanthanum phosphide 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 Lanthanum phosphide in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lanthanum phosphide 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 Lanthanum phosphide out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Lanthanum phosphide in simple terms?

Lanthanum phosphide is an inorganic compound of lanthanum and phosphorus with the chemical formula LaP. Synthesis Lanthanum phosphide can be made by heating lanthanum metal with excess phosphorus in a vacuum: 4 La + P4 → 4 LaP Physical properties Lanthanum phosphide forms black crystals of a cubic…

Why does Lanthanum phosphide 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 Lanthanum phosphide?

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 Lanthanum phosphide.