chemistry

Neodymium(II) iodide

Neodymium(II) iodide 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 Neodymium(II) iodide rather than just read about it. In short: Neodymium(II) iodide or neodymium diiodide is an inorganic salt of iodine and neodymium the formula NdI2. Neodymium uses the +2 oxidation state in the compound.

Key takeaways

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

Reference excerpt

Neodymium(II) iodide or neodymium diiodide is an inorganic salt of iodine and neodymium the formula NdI2. Neodymium uses the +2 oxidation state in the compound. Neodymium(II) iodide is a violet solid. The compound is not stoichiometric. It melts at 562°C.

Preparation Neodymium(II) iodide can be made by heating molten neodymium(III) iodide with neodymium metal at 800 and 580°C for 12 hours. It can also be obtained by reducing neodymium(III) iodide with neodymium in a vacuum at 800 to 900°C:

Nd + 2NdI3 → 3NdI2 The reaction of neodymium with mercury(II) iodide is also possible because neodymium is more reactive than mercury:

Nd + HgI2 → NdI2 + Hg Direct preparation from iodine and neodymium is also possible:

Nd + I2 → NdI2 The compound was first synthesized by John D. Corbett in 1961.

Properties Neodymium(II) iodide is a violet solid. The compound is extremely hygroscopic, and can only be stored and handled under carefully dried inert gas or under a high vacuum. In air it converts into hydrates by absorbing moisture, but these are unstable and more or less rapidly transform into oxide iodides with the evolution of hydrogen:

2NdI2 + 2H2O → 2NdOI + H2↑ + 2HI Neodymium(II) iodide is not stoichiometric, and has a formula of closer to NdI1.95. It melts at 562°C. It has a strontium(II) bromide-type crystal structure. Under pressure, this transforms into the molybdenum disilicide structure typically seen in intermetallic compound, which is already present under normal conditions in other rare earth diiodides (e.g. praseodymium(II) iodide and lanthanum(II) iodide). It forms complexes with tetrahydrofuran and other organic compounds. Neodymium(II) iodide is an electrical insulator.

Reactions Neodymium(II) iodide reacts with organohalides by extracting the halogen, resulting in dimers, oligomers or reactions with the solvent. Solvates are known with tetrahydrofuran and dimethoxyethane: NdI2(THF)2 and NdI2(DME)2. Neodymium(II) iodide reduces hot nitrogen to form an iodide nitride: (NdI2)3N which with THF also gives (NdI)3N2. It reacts with cyclopentadiene in THF to give CpNdI2(THF)3.

Applications Neodymium(II) iodide can be used as a reducing agent or catalyst in organic chemistry.

See also Neodymium(III) iodide Lanthanide

References

Illustrations

Worked examples

Example 1 — a first encounter with Neodymium(II) iodide

Start with the simplest possible case. Write down what Neodymium(II) iodide 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 Neodymium(II) iodide 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 Neodymium(II) iodide 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 Neodymium(II) iodide

In research: Neodymium(II) iodide 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 Neodymium(II) iodide 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: Neodymium(II) iodide is common in secondary-school and first-year university syllabi. It links to neighbouring topics Iodides, Lanthanide halides, Neodymium(II) compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Neodymium(II) iodide 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 Neodymium(II) iodide in 20 minutes

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

Frequently asked questions

What is Neodymium(II) iodide in simple terms?

Neodymium(II) iodide or neodymium diiodide is an inorganic salt of iodine and neodymium the formula NdI2. Neodymium uses the +2 oxidation state in the compound.

Why does Neodymium(II) iodide 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 Neodymium(II) iodide?

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 Neodymium(II) iodide.