chemistry

Magnus's green salt

Magnus's green salt 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 Magnus's green salt rather than just read about it. In short: Magnus's green salt is the inorganic compound with the formula [Pt(NH3)4][PtCl4]. This salt is named after Heinrich Gustav Magnus, who, in the early 1830s, first reported the compound.

Key takeaways

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

Reference excerpt

Magnus's green salt is the inorganic compound with the formula [Pt(NH3)4][PtCl4]. This salt is named after Heinrich Gustav Magnus, who, in the early 1830s, first reported the compound. The compound is a linear chain compound, consisting of a chain of platinum atoms. It is dark green, which is unusual for platinum compounds.

Structure This species has attracted interest in materials chemistry and solid-state physics because of its one-dimensional structure. It contains a chain of alternating [PtCl4]2− anions and [Pt(NH3)4]2+ cations, in which the platinum atoms are separated by 3.25 Å. It is a semiconductor.

Preparation The compound may be prepared by combining aqueous solutions of [Pt(NH3)4]2+ and [PtCl4]2−, which gives a deep green solid precipitate. Under some conditions, this reaction affords a pink polymorph of Magnus's green salt. In this so-called "Magnus's pink salt", the square planar Pt complexes are not stacked.

Related compounds Magnus's green salt is one of three compounds with the empirical formula PtCl2(NH3)2, the others being cisplatin (an important anticancer drug) and transplatin. These cis and trans compounds are molecules, whereas Magnus's green salt is a polymer. This difference is manifested by the solubility of the molecular complexes in water, whereas Magnus's green salt is insoluble. Magnus's green salt occurred as an impurity in early routes to cisplatin from potassium tetrachloroplatinate. Modern production avoids contamination by first converting the tetrachloroplatinate to potassium tetraiodoplatinate, as the iodo ligand's stronger trans effect favors the cis molecule over the polymeric salt. Soluble analogues of Magnus's green salt can be prepared by replacing the ammonia with ethylhexylamine. The corresponding palladium compound ([Pd(NH3)4][PdCl4]) is known as "Vauquelin’s salt".

History Magnus's green salt was one of the first examples of a metal ammine complex.

References

Illustrations

Worked examples

Example 1 — a first encounter with Magnus's green salt

Start with the simplest possible case. Write down what Magnus's green salt 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 Magnus's green salt 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 Magnus's green salt 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 Magnus's green salt

In research: Magnus's green salt 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 Magnus's green salt 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: Magnus's green salt is common in secondary-school and first-year university syllabi. It links to neighbouring topics Ammine complexes, Chemical compounds containing metal–metal bonds, Chloro complexes, so understanding it makes those chapters shorter.
In everyday life: Look for Magnus's green salt 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 Magnus's green salt in 20 minutes

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

Frequently asked questions

What is Magnus's green salt in simple terms?

Magnus's green salt is the inorganic compound with the formula [Pt(NH3)4][PtCl4]. This salt is named after Heinrich Gustav Magnus, who, in the early 1830s, first reported the compound.

Why does Magnus's green salt 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 Magnus's green salt?

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 Magnus's green salt.