science

Oxypnictide

Oxypnictide is a science 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 Oxypnictide rather than just read about it. In short: In chemistry, oxypnictides are a class of materials composed of oxygen, a pnictogen (group-V, especially phosphorus and arsenic) and one or more other elements. Although this group of compounds has been recognized since 1995, interest in these compounds increased dramatically after the publication of the superconducting properties of LaOFeP and LaOFeAs which were discovered in 2006 and 2008.

Key takeaways

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

Reference excerpt

In chemistry, oxypnictides are a class of materials composed of oxygen, a pnictogen (group-V, especially phosphorus and arsenic) and one or more other elements. Although this group of compounds has been recognized since 1995, interest in these compounds increased dramatically after the publication of the superconducting properties of LaOFeP and LaOFeAs which were discovered in 2006 and 2008. In these experiments the oxide was partly replaced by fluoride. These and related compounds (e.g. the 122 iron arsenides) form a new group of iron-based superconductors known as iron pnictides or ferropnictides since the oxygen is not essential but the iron seems to be. Oxypnictides have been patented as magnetic semiconductors in early 2006. The different subclasses of oxypnictides are oxynitrides, oxyphosphides, oxyarsenides, oxyantimonides, and oxybismuthides.

Structure Many of the oxypnictides show a layered structure. For example, LaFePO with layers of La3+O2− and Fe2+P3−. This structure is similar to that of ZrCuSiAs, which is now the parent structure for most of the oxypnictide.

Superconductivity The first superconducting iron oxypnictide was discovered in 2006, based on phosphorus. A drastic increase in the critical temperature was achieved when phosphorus was substituted by arsenic. This discovery boosted the search for similar compounds, like the search for cuprate-based superconductors after their discovery in 1986. The superconductivity of the oxypnictides seems to depend on the iron-pnictogen layers. Some found in 2008 to be high-temperature superconductors (up to 55 K) of composition ReOTmPn, where Re is a rare earth, Tm is a transition metal and Pn is from group V e.g. As.

Tests in magnetic fields up to 45 teslas suggest the upper critical field of LaFeAsO0.89F0.11 may be around 64 T. A different lanthanum-based material tested at 6 K predicts an upper critical field of 122 T in La0.8K0.2FeAsO0.8F0.2.

Practical use Because of the brittleness of the oxypnictides, superconducting wires are formed using the powder-in-tube process (using iron tubes).

Worked examples

Example 1 — a first encounter with Oxypnictide

Start with the simplest possible case. Write down what Oxypnictide claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, 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 Oxypnictide 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 Oxypnictide 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 Oxypnictide

In research: Oxypnictide appears in science 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 Oxypnictide 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: Oxypnictide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Pnictides, Superconductors, so understanding it makes those chapters shorter.
In everyday life: Look for Oxypnictide 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 Oxypnictide in 20 minutes

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

Frequently asked questions

What is Oxypnictide in simple terms?

Why does Oxypnictide matter?

Because it connects several science 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 Oxypnictide?

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 Oxypnictide.