The Spectacular Element Strontium

Introduction to Strontium

Strontium is a silvery-yellow, soft metal element. It’s most commonly known for its uses in flares and red fireworks, but it also used in glow-in-the-dark plastics, in color television, and in modern medicine.

10 Fun Facts about Strontium

The most accurate atomic clock (to one second in the 200 million years) uses strontium atoms.
It’s used in certain toothpastes to aid sensitive teeth.
Strontium is used in cancer therapy due to its characteristic of being the best high-energy beta emitter with the longest lifespan.
China is the top-producer of strontium with roughly 2/3 of the world’s production.
Strontium derives its name from the town it was originally mined from in Scotland, Strontian.
Strontium turns yellow when exposed to air.
The element strontium is the 15th most abundant element in the Earth’s crust.
Due to strontium’s reactivity with the air and water, it is only naturally found in minerals.
The isotope strontium-90 is a component of nuclear fallout.
Refining in glazing often uses compounds containing strontium.

Strontium in the Periodic Table

Strontium has the atomic symbol Sr with an atomic number of 38. It is located in the s-block of the periodic table, below calcium and above barium. The fourth element in the alkaline earth metals on the periodic table is strontium. It has an electron configuration of [Kr]5s². Additionally, the element has an electronegativity of 0.95 on the Pauling scale.

Strontium in Today’s World

Strontium’s Uses in Entertaiment

Chances are that you see strontium active in the world around you every day! Strontium carbonate is used in the making of glass for cathode ray tubes (CRT). One of the main concerns in the creation of televisions was exposing people to X-ray emissions. The use of strontium carbonate in the cathode ray tubes prevents this! However, as the modern day transitions towards more flat-panel technology, television manufacturers no longer need strontium.

Glow-in-the-dark plastics utilized the element strontium. These plastics are “rechargeable” by exposing them to sunlight or to a bright flashlight. Strontium aluminate (and it illuminates!) has the phosphorescent quality that slowly allows it to re-emit light over a certain period of time.

Strontium creates vibrant red salts. As previously mentioned, these red salts produce flare guns and red fireworks. This is also due to its reactivity with the air at room temperature.

Strontium in Medicine

The element strontium is used in multiple types of medicines. The most common of these is in the treatment of osteoporosis and tooth decay. Strontium increases your bone mineral density and reduces the risk of bone fractures. That is why it is used to treat osteoporosis. Since your teeth are also bones, it helps to decrease your risk of cavities as well! A radioactive form of strontium, available in dietary supplements, treats cancer due to its ability to destroy cancer cells.

Where is the Strontium Element Found?

Strontium is found naturally in soil, bedrock and groundwater. It’s most commonly found in the minerals celestite and strontianite.

When and How was Strontium Discovered?

In 1787, a strange rock was found in a coal mine in Strontian, Scotland. An Edinburgh doctor, Adair Crawford identified the rock as a new mineral and called it “strontia”. Four years later in 1791, Thomas Charles Hope discovered the mineral contained a new element, strontium, that burned red under a flame. In 1808, isolation of strontium occurred.

Strontium in Chemistry – Compounds, Reactions, Isotopes, Oxidation States

Strontium Element Compounds and Reactions

Oxides: SrO
Halides: SrI₂, SrBr₂, SrCl₂,
Salts: SrCO₃, Sr(NO₃)₂, Sr₃N₂

When exposed to the air, strontium reacts slowly to give strontium oxide and strontium nitride.

$\begin{align*} 2Sr(\text{s}) + O_{2}(\text{g}) \rightarrow 2SrO(\text{s}) \end{align*}$

$\begin{align*} 3Sr(\text{s}) + N_{2}(\text{g}) \rightarrow Sr_{3}N_{2}(\text{s}) \end{align*}$

When placed in water, strontium also reacts, just very slowly. The metal then sinks to the bottom and if left unattended, it will form little bubbles of hydrogen gas on the surface of the metal.

$\begin{align*} Sr(\text{s}) + 2H_{2}O(\text{l}) \rightarrow Sr(OH)_{2}(\text{aq}) + H_{2}(\text{g}) \end{align*}$

The reaction between strontium and chlorides occurs between bromine, chlorine, and iodine. However, chemists call the reaction of bromine and iodine endothermic, meaning it requires heat to take place.

$\begin{align*} Sr(\text{s}) + Cl_{2}(\text{g}) &\rightarrow SrCl_{2}(\text{s}) \\ Sr(\text{s}) + Br_{2}(\text{g}) &\rightarrow SrBr_{2}(\text{s}) \\ Sr(\text{s}) + I_{2}(\text{g}) &\rightarrow SrI_{2}(\text{s}) \end{align*}$

Isolation of Elemental Strontium

In 1808, Sir Humphry Davy using electrolysis, isolated the element strontium. He mixed magnesium oxide and strontium sulfate. The electrodes were the metals mercury and platinum. A strontium and magnesium mixture formed around the mercury electrode. He then heated this mixture which left just strontium metal around the electrode.

Strontium Isotopes

There exist four stable isotopes of strontium; strontium-84, strontium-86, strontium-87, and strontium-88.

Oxidation States of Strontium Element

Strontium only has one oxidation of +2.

Properties of Strontium Element

Atomic Symbol: Sr
Melting point: 769°C
Boiling point: 1384°C
Density: 2.54 g/ml
Atomic weight: 87.62g
Atomic number: 38
Electronegativity: 0.95
Molar heat capacity: 26.4 J/(mol*K)
Classification: alkaline earth metal
Natural abundance in the Earth’s crust: 360 ppm
Electron shell configuration: [Kr]5s²
Stable Isotopes: strontium-84, strontium-86, strontium-87, and strontium-88.
Found naturally in the soil, bedrock and groundwater
Toxicity: Those with calcium deficiencies are at higher risk of birth defects and other complications from strontium exposure due to its similarity in structure to calcium. Otherwise, strontium is non-toxic.

Where Can I Buy The Strontium Element?

Strontium is a relatively common element and thus sells for relatively cheap! You can buy it from online sellers such as Lucretia for $7.25 for 10 grams!