chemistry

Samarium(III) chloride

Samarium(III) chloride 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 Samarium(III) chloride rather than just read about it. In short: Samarium(III) chloride, also known as samarium trichloride, is an inorganic compound of samarium and chloride. It is a pale yellow salt that rapidly absorbs water to form a hexahydrate, SmCl3.6H2O.

Key takeaways

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

Reference excerpt

Samarium(III) chloride, also known as samarium trichloride, is an inorganic compound of samarium and chloride. It is a pale yellow salt that rapidly absorbs water to form a hexahydrate, SmCl3.6H2O. The compound has few practical applications but is used in laboratories for research on new compounds of samarium.

Structure Like several related chlorides of the lanthanides and actinides, SmCl3 crystallises in the UCl3 motif. The Sm3+ centres are nine-coordinate, occupying trigonal prismatic sites with additional chloride ligands occupying the three square faces.

Preparation and reactions SmCl3 is prepared by the "ammonium chloride" route, which involves the initial synthesis of (NH4)2[SmCl5]. This material can be prepared from the common starting materials at reaction temperatures of 230 °C from samarium oxide:

10 NH4Cl + Sm2O3 → 2 (NH4)2[SmCl5] + 6 NH3 + 3 H2O The pentachloride is then heated to 350-400 °C resulting in evolution of ammonium chloride and leaving a residue of the anhydrous trichloride:

(NH4)2[SmCl5] → 2 NH4Cl + SmCl3 It can also be prepared from samarium metal and hydrochloric acid.

2 Sm + 6 HCl → 2 SmCl3 + 3 H2 Aqueous solutions of samarium(III) chloride can be prepared by dissolving metallic samarium or samarium carbonate in hydrochloric acid. Samarium(III) chloride is a moderately strong Lewis acid, which ranks as "hard" according to the HSAB concept. Aqueous solutions of samarium chloride can be used to prepare samarium trifluoride:

SmCl3 + 3 KF → SmF3 + 3 KCl

Uses Samarium(III) chloride is used for the preparation of samarium metal, which has a variety of uses, notably in magnets. Anhydrous SmCl3 is mixed with sodium chloride or calcium chloride to give a low melting point eutectic mixture. Electrolysis of this molten salt solution gives the free metal.

In laboratory Samarium(III) chloride can also be used as a starting point for the preparation of other samarium salts. The anhydrous chloride is used to prepare organometallic compounds of samarium, such as bis(pentamethylcyclopentadienyl)alkylsamarium(III) complexes.

References

Illustrations

Samarium(III) chloride: Samarium(III)_chloride_hexahydrate — Samarium(III)_chloride_hexahydrate

Worked examples

Example 1 — a first encounter with Samarium(III) chloride

Start with the simplest possible case. Write down what Samarium(III) chloride 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 Samarium(III) chloride 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 Samarium(III) chloride 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 Samarium(III) chloride

In research: Samarium(III) chloride 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 Samarium(III) chloride 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: Samarium(III) chloride is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chlorides, Lanthanide halides, Samarium(III) compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Samarium(III) chloride 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 Samarium(III) chloride in 20 minutes

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

Frequently asked questions

What is Samarium(III) chloride in simple terms?

Samarium(III) chloride, also known as samarium trichloride, is an inorganic compound of samarium and chloride. It is a pale yellow salt that rapidly absorbs water to form a hexahydrate, SmCl3.6H2O.

Why does Samarium(III) chloride 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 Samarium(III) chloride?

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 Samarium(III) chloride.