chemistry

Radium chloride

Radium 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 Radium chloride rather than just read about it. In short: Radium chloride is an inorganic compound with the chemical formula RaCl2. It is a radium salt of hydrogen chloride.

Key takeaways

Radium 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 Radium chloride to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Radium chloride from memory before moving on to harder problems.

Reference excerpt

Radium chloride is an inorganic compound with the chemical formula RaCl2. It is a radium salt of hydrogen chloride. It was the first radium compound isolated in a pure state. Marie Curie and André-Louis Debierne used it in their original separation of radium from barium. The first preparation of radium metal was by the electrolysis of a solution of this salt using a mercury cathode.

Preparation Radium chloride crystallises from aqueous solution as the dihydrate. The dihydrate is dehydrated by heating to 100 °C in air for one hour followed by 5.5 hours at 520 °C under argon. If the presence of other anions is suspected, the dehydration may be effectuated by fusion under hydrogen chloride. Radium chloride can also be prepared by heating radium bromide in a flow of dry hydrogen chloride gas. It can be produced by treating radium carbonate with hydrochloric acid.

Properties Radium chloride is a colorless salt with a blue-green luminescence, especially when heated. Its color gradually changes to yellow with aging, whereas contamination by barium may impart a rose tint. It is less soluble in water than other alkaline earth metal chlorides – at 25 °C its solubility is 245 g/L whereas that of barium chloride is 307 g/L, and the difference is even larger in hydrochloric acid solutions. This property is used in the first stages of the separation of radium from barium by fractional crystallization. Radium chloride is only sparingly soluble in azeotropic hydrochloric acid and virtually insoluble in concentrated hydrochloric acid. Gaseous RaCl2 shows strong absorptions in the visible spectrum at 676.3 nm and 649.8 nm (red): the dissociation energy of the radium–chlorine bond is estimated as 2.9 eV, and its length as 292 pm. Contrary to diamagnetic barium chloride, radium chloride is weakly paramagnetic with a magnetic susceptibility of 1.05×10−6. Its flame color is red.

Uses Radium chloride is still used for the initial stages of the separation of radium from barium during the extraction of radium from pitchblende. The large quantities of material involved (to extract a gram of pure radium metal, about 7 tonnes of pitchblende is required) favour this less costly (but less efficient) method over those based on radium bromide or radium chromate (used for the later stages of the separation). It was also used in medicine to produce radon gas which in turn was used as a brachytheraputic cancer treatment. Radium-223 dichloride (USP, radium chloride Ra 223), tradename Xofigo (formerly Alpharadin), is an alpha-emitting radiopharmaceutical. Bayer received FDA approval for this drug to treat castration-resistant prostate cancer with bone metastases in May 2013. The dose in ranges from 46-250 kBq/kg.

References

Bibliography Gmelins Handbuch der anorganischen Chemie (8. Aufl.), Berlin:Verlag Chemie, 1928, pp. 60–61. Weigel, Fritz [in German] (1977). Gmelin Handbuch der anorganischen Chemie (8. Aufl. 2. Ergänzungsband). Gmelin Handbook of Inorganic Chemistry (8th ed.). Berlin: Springer. p. 362–364. ISBN 978-3-540-93335-9.

Illustrations

Worked examples

Example 1 — a first encounter with Radium chloride

Start with the simplest possible case. Write down what Radium 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 Radium 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 Radium 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 Radium chloride

In research: Radium 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 Radium 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: Radium chloride is common in secondary-school and first-year university syllabi. It links to neighbouring topics Alkaline earth metal halides, Chlorides, Radium compounds, so understanding it makes those chapters shorter.
In everyday life: Look for Radium 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.

Ask Teacher Smith questions about this articleOpens your AI tutor with a question about “Radium chloride” →

Affiliate

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

How to study Radium chloride in 20 minutes

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

Frequently asked questions

What is Radium chloride in simple terms?

Radium chloride is an inorganic compound with the chemical formula RaCl2. It is a radium salt of hydrogen chloride.

Why does Radium 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 Radium 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 Radium chloride.