chemistry

Trirhenium nonachloride

Trirhenium nonachloride 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 Trirhenium nonachloride rather than just read about it. In short: Trirhenium nonachloride is a compound with the formula ReCl3, sometimes also written Re3Cl9. It is a dark red hygroscopic solid that is insoluble in ordinary solvents.

Key takeaways

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

Reference excerpt

Trirhenium nonachloride is a compound with the formula ReCl3, sometimes also written Re3Cl9. It is a dark red hygroscopic solid that is insoluble in ordinary solvents. The compound is important in the history of inorganic chemistry as an early example of a cluster compound with metal-metal bonds. It is used as a starting material for synthesis of other rhenium complexes.

Structure and physical properties As shown by X-ray crystallography trirhenium nonachloride consists of Re3Cl12 subunits that share three chloride bridges with adjacent clusters. The interconnected network of clusters forms sheets. Around each Re center are seven ligands, four bridging chlorides, one terminal chloride, and two Re-Re bonds.

The hydrate is molecular with the formula Re3Cl9(H2O)3. The heat of oxidation is evaluated according to the equation:

1/3 Re3Cl9 + 4 OH− + 2 OCl− → ReO4− + 2 H2O + 5Cl− The enthalpy for this process is 190.7 ± 0.2 kcal/mol.

Preparation and reactions The compound was discovered in 1932. Trirhenium nonachloride is efficiently prepared by thermal decomposition of rhenium pentachloride or hexachlororhenic(IV) acid:

3 ReCl5 → Re3Cl9 + 3 Cl2 If the sample is vacuum sublimed at 500 °C, the resulting material is comparatively unreactive. The partially hydrated material such as Re3Cl9(H2O)4 can be more useful synthetically. Other synthetic methods include treating rhenium with sulfuryl chloride. This process is sometimes conducted with the addition of aluminium chloride. It is also obtained by heating Re2(O2CCH3)4Cl2 under HCl:

3/2 Re2(O2CCH3)4Cl2 + 6 HCl → Re3Cl9 + 6 HO2CCH3 Reaction of the tri- and pentachlorides gives rhenium tetrachloride:

3 ReCl5 + Re3Cl9 → 6 ReCl4

References

Worked examples

Example 1 — a first encounter with Trirhenium nonachloride

Start with the simplest possible case. Write down what Trirhenium nonachloride 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 Trirhenium nonachloride 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 Trirhenium nonachloride 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 Trirhenium nonachloride

In research: Trirhenium nonachloride 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 Trirhenium nonachloride 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: Trirhenium nonachloride is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical compounds containing metal–metal bonds, Chlorides, Metal halides, so understanding it makes those chapters shorter.
In everyday life: Look for Trirhenium nonachloride 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 Trirhenium nonachloride in 20 minutes

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

Frequently asked questions

What is Trirhenium nonachloride in simple terms?

Trirhenium nonachloride is a compound with the formula ReCl3, sometimes also written Re3Cl9. It is a dark red hygroscopic solid that is insoluble in ordinary solvents.

Why does Trirhenium nonachloride 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 Trirhenium nonachloride?

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 Trirhenium nonachloride.