top of page

Strontium Sr

 

Where is strontium used--or where does it impact our everyday lives?

 

Strontium

Symbol: Sr  Atomic #: 38

Atomic mass: 87.62

Periodic Table: Group 2, Period 5

Melting point: 777oC   (1431oF)

Boiling point: 1377oC   (2511oF)

Density: 2.64 g/mL

Three main isotopes: 88Sr (82.58%), 88Sr (82.58%), 87Sr (7.0%)

Electron configuration: [Kr] 5s2

Found in nature: minerals celestite, strontianite

Abundance Earth’s crust: 370 milligrams per kilogram

% Abundance Universe: 4.0 x 10^-6 %

Extracted from: Celestite, Strontianite

How: Reduction of strontium oxide with aluminum

Amount used per year, US: 2.5 tons

Amount used per year, World: Worldwide resources of strontium exceed 1 billion tons.

Cost (2015 US $): $100 per 100g

Uses of the element:­­­­­­­­­­

  • Producing glass (cathode ray tubes) for non-flat screen color televisions. Also used to produce ferrite ceramic magnets and refining zinc

  • World’s most accurate atomic clock (accurate to one second in 200 million years) developed using strontium atoms

  • Strontium salts used in flares and fireworks (crimson color)

  • Strontium chloride used in toothpaste for sensitive teeth

  • Strontium oxide used to improve quality of pottery glazes

  • Isotope 90Sr is one of the best-lived, high-energy beta emitters known – used in cancer therapy

Amount in the adult body: 320 mg

  • Recommended amount: 680 milligrams per day (strontium ranelate)

  • 99% found in bones

Reactivity with air (oxygen):

2Sr(s) + O2(g) → 2SrO(s)

3Sr(s) + N2(g) → Sr3N2(s)

When ignited, burns in air = mixture of white strontium oxide (SrO) and strontium nitride (Sr3N2)

Reactivity with water:

Sr(s) + 2H2O(g) → Sr(OH)2(aq) + H2(g)

Slow reaction - strontium hydroxide (Sr(OH)2) and hydrogen gas (H2)

Strontium metal sinks in water bubbles of hydrogen stick to the surface of the metal

Reactivity with acids or alkalis:

Sr(s) + 2HCl(aq) → Sr2+(aq) + 2Cl-(aq) + H2(g)

Strontium metal dissolves in dilute or concentrated HCl - forms solutions containing aqueous Sr(II) ion together with H2.

 

Lanl.gov  Researcher Joanna B.

 

Image to left/above is strontianite is strontium carbonate, SrCO3, from Leogang, Salzburg, Austria viewed at the National Museum of Natural History in Washington D.C., USA during a Chemistry One field trip

Photographers: Class of 2019, Antoine L, Lulu M, and Lily S

 

Below left is another sanple of strontianite is strontium carbonate, SrCO3, from Drensteinfurt, Nord Rhein-Westphalen, Germany

Photographers: Class of 2019, Antoine L, Lulu M, and Lily S.

Below are glow-in-the-dark stars arranged in the Orion, Ursa Major constellations by Alya A-K.  The material is phosphorescent and absorbs energy quickly but releases it slowly as light.  One effective phosphorescent material is strontium aluminate, SrAl2O4

There is often Europium present which activates the photoluminescent phosphor. Photographer Alya A-K

To the left is the mineral celesite, SrSO4, from Madagascar contains strontium.  The gem is a 16.8 carat gem viewed at the National Museum of Natural History in Washington D.C., USA during a Chemistry One field trip

WIS Photographer

A radioactive sample of strontium-90.  It decays with beta emissions--high energy electrons--to give yttrium

 

  90Sr -->  90Y + e-

Another sample of celesite, here with aragonite, SrSO4, from Agrigento, Sicilia, Italy on display at the National Museum of Natural History in Washington D.C. viewed during a Chemistry One field trip.

WIS Photographer

Glow in the dark materials are phosphorescent because the electrons in the materials are excited by sunlight and can be seen releasing that energy when it is dark.  The phosphors are made of materials like strontium aluminate or zinc sulfide

See the Orian constellation on Alya A-K's ceiling.

Photogrpher Alya A-K

bottom of page