chemistry

Lutetium compounds

Lutetium compounds 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 Lutetium compounds rather than just read about it. In short: Lutetium compounds are compounds formed by the lanthanide metal lutetium (Lu). In these compounds, lutetium generally exhibits the +3 oxidation state, such as LuCl3, Lu2O3 and Lu2(SO4)3.

Key takeaways

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

Reference excerpt

Lutetium compounds are compounds formed by the lanthanide metal lutetium (Lu). In these compounds, lutetium generally exhibits the +3 oxidation state, such as LuCl3, Lu2O3 and Lu2(SO4)3. Aqueous solutions of most lutetium salts are colorless and form white crystalline solids upon drying, with the common exception of the iodide. The soluble salts, such as nitrate, sulfate and acetate form hydrates upon crystallization. The oxide, hydroxide, fluoride, carbonate, phosphate and oxalate are insoluble in water.

Oxides

Lutetium(III) oxide is a white solid, a cubic compound of lutetium which sometimes used in the preparation of specialty glasses. It is also called lutecia. It is a lanthanide oxide, also known as a rare earth. Lutetium(III) oxide is an important raw material for laser crystals. It also has specialized uses in ceramics, glass, phosphors, and lasers. Lutetium(III) oxide is used as a catalyst in cracking, alkylation, hydrogenation, and polymerization. The band gap of lutetium oxide is 5.5 eV.

Halides Lutetium(III) fluoride can be produced by reacting lutetium oxide with hydrogen fluoride, or reacting lutetium chloride and hydrofluoric acid. It can also be produced by reacting lutetium sulfide and hydrofluoric acid:

3 Lu2S3+ 20 HF + (2 + 2x) H2O → 2 (H3O)Lu3F10·xH2O↓ + 9 H2S↑ (x = 0.9) (H3O)Lu3F10 → 3 LuF3 + HF↑ + H2O↑ Lutetium oxide and nitrogen trifluoride react at 240 °C to produce LuOF. A second step happens below 460 °C to produce LuF3. Lutetium(III) chloride forms hygroscopic white monoclinic crystals and also a hydroscopic hexahydrate LuCl3·6H2O. Anhydrous lutetium(III) chloride has the YCl3 (AlCl3) layer structure with octahedral lutetium ions. Lutetium(III) bromide can be synthesized through the following reaction:

2 Lu(s) + 3 Br2(g) → 2 LuBr3(s) If burned, lutetium(III) bromide may produce hydrogen bromide and metal oxide fumes. Lutetium(III) bromide reacts to strong oxidizing agents. Lutetium(III) iodide can be obtained by reacting lutetium with iodine:

2 Lu + 3 I2 → LuI3 Lutetium(III) iodide can also obtained by the reacting metallic lutetium with mercury iodide in vacuum at 500 °C:

2 Lu + 3 HgI2 → 2 LuI3 + 3 Hg The elemental mercury generated in the reaction can be removed by distillation. The lutetium(III) iodide hydrate crystallized from the solution can be heated with ammonium iodide to obtain the anhydrate.

Coordination compounds

Nitrogen-containing ligand complexes

Lutetium phthalocyanine

Lutetium phthalocyanine is the most notable coordination compound of lutetium, and is derived from lutetium and two phthalocyanines. It was the first known example of a molecule that is an intrinsic semiconductor. It exhibits electrochromism, changing color when subject to a voltage. It is a double-decker sandwich compound consisting of a Lu3+ ion coordinated to two the conjugate base of two phthalocyanines. The rings are arranged in a staggered conformation. The extremities of the two ligands are slightly distorted outwards. The complex features a non-innocent ligand, in the sense that the macrocycles carry an extra electron. It is a free radical with the unpaired electron sitting in a half-filled molecular orbital between the highest occupied and lowest unoccupied orbitals, allowing its electronic properties to be finely tuned. It, along with many substituted derivatives like the alkoxy-methyl derivative Lu[(C8H17OCH2)8Pc]2, can be deposited as a thin film with intrinsic semiconductor properties; said properties arise due to its radical nature and its low reduction potential compared to other metal phthalocyanines. This initially green film exhibits electrochromism; the oxidized form LuPc+2 is red, whereas the reduced form LuPc−2 is blue and the next two reduced forms are dark blue and violet, respectively. The green/red oxidation cycle can be repeated over 10,000 times in aqueous solution with dissolved alkali metal halides, before it is degraded by hydroxide ions; the green/blue redox degrades faster in water.

Other complexes [LuI2(HOiPr)4]I can be dissolved in pyridine-THF to give yellow [LuI(OiPr)(py)5]I. LuI3 is directly dissolved in pyridine-THF to obtain yellow [LuI2(py)5]I. In both compounds pyridine is coordinated to lutetium by nitrogen atom. Lutetium(III) nitrate can be crystallized with 2,2':6',2"-terpyridine (terpy) in dry acetonitrile to obtain colorless [Lu(terpy)(NO3)3], in which the nitrogen atom and the oxygen atom of the nitrate are coordinated to the lutetium atom.

Oxygen-containing ligand complexes

Trivalent lutetium and water can form complex ions such as [Lu(OH2)n]3+, and lutetium(III) perchlorate and lutetium(III) trifluoromethanesulfonate can exist in the form of hydrates. Ether (R2O) is also a common oxygen-containing ligand. For example, Lu(CH2SiMe3)3(THF)2 can be obtained by reacting lutetium(III) chloride and (trimethylsilyl)methyllithium in a solvent containing tetrahydrofuran (THF).

Other compounds Adding ammonia water or a hydroxide to the aqueous solution of any soluble lutetium salt can precipitate lutetium(III) hydroxide (Lu(OH)3). The hexagonal lutetium hydroxide can be heated and dehydrated to obtain the monoclinic lutetium oxyhydroxide (LuO(OH)), and further heating will make it decompose into lutetium(III) oxide (Lu2O3). Lutetium oxyhalides (LuOX, X=Cl, Br, I) can be obtained by hydrolysis of the lutetium trihalides. Lu2Cl2C can be obtained by reacting lutetium(III) chloride, caesium chloride, lutetium and carbon at a high temperature.

References

Illustrations

Worked examples

Example 1 — a first encounter with Lutetium compounds

Start with the simplest possible case. Write down what Lutetium compounds 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 Lutetium compounds 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 Lutetium compounds 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 Lutetium compounds

In research: Lutetium compounds 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 Lutetium compounds 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: Lutetium compounds is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical compounds by element, Lutetium, Lutetium compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Lutetium compounds 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 Lutetium compounds in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Lutetium compounds means in your own words.
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Frequently asked questions

What is Lutetium compounds in simple terms?

Lutetium compounds are compounds formed by the lanthanide metal lutetium (Lu). In these compounds, lutetium generally exhibits the +3 oxidation state, such as LuCl3, Lu2O3 and Lu2(SO4)3.

Why does Lutetium compounds 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 Lutetium compounds?

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 Lutetium compounds.