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Strontium

physical science Maturity 7-9 Next article →

Strontium is a chemical element with the symbol Sr and the atomic number 38. It belongs to a group called the alkaline earth metals. This element is a soft, silver-white metal with a pale yellow tint.

Strontium 1
Strontium 1

Strontium is highly chemically reactive, meaning it changes easily when it touches other substances. Because of this reactivity, it does not stay pure in nature. Instead, it is always found combined with other elements in minerals. It is the 15th most abundant element in the Earth's crust.

Celestine Poland
Celestine Poland

In the natural world, strontium is mostly found in two minerals. The first is celestine, which is a sulfate mineral. The second is strontianite, which is a carbonate mineral.

Celestine Poland
Celestine Poland

Because strontium reacts so quickly with oxygen and water, it only exists in these combined forms. When the metal is exposed to air, it forms a dark oxide layer. If the metal is in a very fine powder, it becomes pyrophoric. This means it can ignite spontaneously just by touching the air at room temperature. To keep it safe, scientists store the metal under liquids like mineral oil or kerosene.

Strontium has physical properties that sit between its neighbors, calcium and barium. It is softer than calcium but harder than barium. Its melting point is 777 °C, which is lower than calcium's 842 °C. Its boiling point is 1377 °C, also lower than calcium's 1484 °C. The density of strontium is 2.64 g/cm3. This value is intermediate between calcium at 1.54 g/cm3 and barium at 3.594 g/cm3.

Strontium 1
Strontium 1

These similarities make it useful for many chemical processes.

The history of strontium began in the village of Strontian, Scotland. In 1790, Adair Crawford and William Cruickshank discovered ores there that behaved differently than other minerals. Later, a professor named Thomas Charles Hope proposed the name "strontites" to honor the location. In 1808, the scientist Humphry Davy finally isolated the metal. He used a process called electrolysis, which uses electricity to break down chemical mixtures. Davy eventually settled on the name strontium for the element.

Celestine Poland
Celestine Poland

Strontium has been used in many different industries over time. During the 19th century, it was vital for making sugar from sugar beets. The German sugar industry used the "strontian process" for a long time. Before the digital age, strontium was used heavily in electronics. At the peak of cathode-ray tube television production, 75% of strontium used in the United States went into making faceplate glass.

Monitor.arp
Monitor.arp

As television technology changed, the demand for strontium in this area declined significantly.

One of the most famous uses of strontium is in pyrotechnics. When strontium salts are burned, they produce a bright, crimson-red flame.

FlammenfärbungSr
FlammenfärbungSr

This effect is used to make red colors in fireworks and flares.

Ignis Brunensis 2010-05-22 (5)
Ignis Brunensis 2010-05-22 (5)

Scientists also study its isotopes, which are different versions of the same element. Most natural strontium is the stable isotope strontium-88, making up about 82.6% of all natural strontium. Other isotopes, like strontium-87, help scientists with rubidium–strontium dating to find the age of materials.

However, some versions of strontium can be dangerous. The synthetic isotope strontium-90 is radioactive and is produced during nuclear fission.

Soviet RTG
Soviet RTG

Because strontium is chemically similar to calcium, the human body absorbs it in a similar way. If a person absorbs strontium-90, it can settle in the bones. This can lead to serious health issues like leukemia or bone cancer. The 1986 Chernobyl accident released a large amount of this isotope into the environment.

Soviet RTG
Soviet RTG

Understanding these connections between chemistry and biology is essential for safety.

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🖼️ Images & Media (6)
File:Strontium 1.jpg
Strontium 1.jpg
File:FlammenfärbungSr.png
FlammenfärbungSr.png
File:Celestine Poland.jpg
Celestine Poland.jpg
File:Monitor.arp.jpg
Monitor.arp.jpg
File:Ignis Brunensis 2010-05-22 (5).jpg
Ignis Brunensis 2010-05-22 (5).jpg
File:Soviet RTG.jpg
Soviet RTG.jpg
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