chemistry

Iron(III) perchlorate

Iron(III) perchlorate 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 Iron(III) perchlorate rather than just read about it. In short: Iron(III) perchlorate, also known as ferric perchlorate, is an inorganic chemical compound with the formula Fe(ClO4)3·nH2O, where n can range from 0 to 9. The most common form is the nonahydrate, Fe(ClO4)3·9H2O, which is a hygroscopic pale violet crystalline solid, but samples are often partially hydrolyzed and/or contaminated with iron(III) chloride, giving them a yellow color.

Key takeaways

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

Reference excerpt

Iron(III) perchlorate, also known as ferric perchlorate, is an inorganic chemical compound with the formula Fe(ClO4)3·nH2O, where n can range from 0 to 9. The most common form is the nonahydrate, Fe(ClO4)3·9H2O, which is a hygroscopic pale violet crystalline solid, but samples are often partially hydrolyzed and/or contaminated with iron(III) chloride, giving them a yellow color.

History Iron(III) perchlorate was first observed by Georges-Simon Serullas in 1831 as an oxidation product of iron(II) perchlorate, who was attempting to produce various metal perchlorates after Friedrich von Stadion discovered the perchlorate ion. However, it was not properly characterized until 1935 by Folke Lindstrand.

Preparation The nonahydrate is produced by refluxing a mixture of iron(III) oxide-hydroxide and aqueous 70% perchloric acid:

FeO(OH) + 3 HClO4 → Fe(ClO4)3 + 2 H2O It can also be prepared by the reaction of iron(III) chloride and aqueous perchloric acid, followed by repeated recrystallization in perchloric acid. In comparison, the synthesis of the anhydrous form is much more difficult. It is produced by the reaction of iron(III) chloride and dichlorine hexoxide at 20 °C:

2 FeCl3 + 7 Cl2O6 → ClO2Fe2(ClO4)7 + 6 ClO2 + 3 Cl2 The resulting ClO2Fe2(ClO4)7 is heated under a vacuum at 60 °C to yield the canary yellow anhydrous iron(III) perchlorate. Hydrates other than the nonahydrate, such as the hexahydrate, from the dehydration of the nonahydrate in the presence of sulfuric acid, and the dihydrate, from the reaction of anhydrous perchloric acid and iron(III) chloride, have been reported.

Structure The nonahydrate, structurally formulated [Fe(H2O)6](ClO4)3·3H2O, has a trigonal crystal structure and consists of discrete octahederal [Fe(H2O)6]3+ centers as well as perchlorate and three molecules of water of crystallization. The anhydrous form, which has been probed by IR spectroscopy, consists of bidentate perchlorate ligands.

Reactions and applications Iron(III) perchlorate dissolves in water to form [Fe(H2O)6]3+ and ClO4– ions. The [Fe(H2O)6]3+ partially hydrolyses:

[Fe(H2O)6]3+ ⇌ [Fe(H2O)5OH]2+ + H+ Dilute solutions of iron(III) perchlorate slowly precipitate iron(III) hydroxide particles, whereas concentrated solutions do not, because the higher acidity prevents hydroxide formation. Hydrolysis can also be suppressed by adding perchloric acid. The above behavior parallels that of iron(III) nitrate solutions. The nonahydrate decomposes at around 110 °C to an unknown basic perchlorate. The anhydrous form, when heated, similarly decomposes to an unknown basic perchlorate. Iron(III) perchlorate has very limited applications in organic synthesis. The anhydrous and dihydrate have been studied as a cationic polymerization initiator for alkenes. The nonahydrate has been studied for use as a catalyst in various organic reactions, including multicomponent condensation reactions.

References

Illustrations

Worked examples

Example 1 — a first encounter with Iron(III) perchlorate

Start with the simplest possible case. Write down what Iron(III) perchlorate 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 Iron(III) perchlorate 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 Iron(III) perchlorate 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 Iron(III) perchlorate

In research: Iron(III) perchlorate 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 Iron(III) perchlorate 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: Iron(III) perchlorate is common in secondary-school and first-year university syllabi. It links to neighbouring topics Iron(III) compounds, Perchlorates, so understanding it makes those chapters shorter.
In everyday life: Look for Iron(III) perchlorate 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Iron(III) perchlorate” →

Affiliate

Preply — study more efficiently by working with a personal tutor. 50% off.

How to study Iron(III) perchlorate in 20 minutes

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

Frequently asked questions

What is Iron(III) perchlorate in simple terms?

Why does Iron(III) perchlorate 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 Iron(III) perchlorate?

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 Iron(III) perchlorate.