chemistry

Schweizer's reagent

Schweizer's reagent 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 Schweizer's reagent rather than just read about it. In short: Schweizer's reagent is a metal ammine complex with the formula [Cu(NH3)4(H2O)2](OH)2. This deep-blue compound is used in purifying cellulose.

Key takeaways

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

Reference excerpt

Schweizer's reagent is a metal ammine complex with the formula [Cu(NH3)4(H2O)2](OH)2. This deep-blue compound is used in purifying cellulose. It is a salt, consisting of tetraamminediaquacopper(II) cations ([Cu(NH3)4(H2O)2]2+) and hydroxide anions (OH−). It is prepared by dissolving copper(II) hydroxide in an aqueous solution of ammonia. It forms an azure solution. Evaporation of these solutions leaves light blue residue of copper hydroxide, reflecting the lability of the copper-ammonia bonding. If conducted under a stream of ammonia, then deep blue needle-like crystals of the tetrammine form. In presence of oxygen, concentrated solutions give rise to nitrites Cu(NO2)2(NH3)n. The nitrite results from oxidation of the ammonia.

Reactions with cellulose Schweizer's reagent was once used in production of cellulose products such as rayon and cellophane (see cupro). Cellulose, which is quite insoluble in water (hence its utility as clothing), dissolves in the presence of Schweizer's reagent. Using the reagent, cellulose can be extracted from wood pulp, cotton fiber, and other natural cellulose sources. Cellulose precipitates when the solution is acidified. It functions by binding to vicinal diols. Presently, the reagent is used in the analysis of the molecular weight of cellulose samples.

History These properties of Schweizer's reagent were discovered by the Swiss chemist Matthias Eduard Schweizer (1818–1860), after whom the reagent is named. The French chemist Louis-Henri Despeissis then proposed a procedure where cellulose is extruded into diluted sulphuric acid. This leads to the complex no longer being stable enough to hold the cellulose in solution and it precipitates out forming strings. These strings were later used in industry to make artificial silk which was called rayon in the US and viscose in the UK. It was also originally used to make cellophane.

Footnotes

References Eduard Schweizer (1857). "Das Kupferoxyd-Ammoniak, ein Auflösungsmittel für die Pflanzenfaser" [Copper ammonium oxide, a solvent for plant fibers]. Journal für praktische Chemie. 72 (1): 109–111. doi:10.1002/prac.18570720115. George B Kauffman (1984). "Eduard Schweizer (1818-1860): The Unknown Chemist and His Well-Known Reagent". J. Chem. Educ. 61 (12): 1095–1097. Bibcode:1984JChEd..61.1095K. doi:10.1021/ed061p1095.

Illustrations

Worked examples

Example 1 — a first encounter with Schweizer's reagent

Start with the simplest possible case. Write down what Schweizer's reagent 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 Schweizer's reagent 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 Schweizer's reagent 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 Schweizer's reagent

In research: Schweizer's reagent 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 Schweizer's reagent 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: Schweizer's reagent is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ammine complexes, Copper complexes, Hydroxides, so understanding it makes those chapters shorter.
In everyday life: Look for Schweizer's reagent 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 “Schweizer's reagent” →

Affiliate

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

How to study Schweizer's reagent in 20 minutes

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

Frequently asked questions

What is Schweizer's reagent in simple terms?

Schweizer's reagent is a metal ammine complex with the formula [Cu(NH3)4(H2O)2](OH)2. This deep-blue compound is used in purifying cellulose.

Why does Schweizer's reagent 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 Schweizer's reagent?

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 Schweizer's reagent.