|
38
Sr
87.62
|
Strontium nitrate produces a red color in pyrotechnic displays. Strontium is the source of the red color.
| Classification: | Strontium is an alkali earth metal |
| Color: | silvery |
| Atomic weight: | 87.62 |
| State: | solid |
| Melting point: | 777 oC, 1050 K |
| Boiling point: | 1380 oC, 1653 K |
| Shells: | 2,8,18,8,2 |
| Electron configuration: | [Kr] 5s2 |
| Density @ 20oC: | 2.6 g/cm3 |
| Atomic volume: | 33.7 cm3/mol |
| Structure: | ccp: cubic close-packed |
| Hardness: | 1.5 mohs |
Strontium. Photo by Matthias Zepper.
Discovery of Strontium
Strontium was recognized as distinct from barium in 1790 by Adair Crawford in a mineral sample from a lead mine near Strontian, Scotland.
The mineral took its name from the Scottish town and was called strontianite (strontium carbonate).
The metal was first isolated by Sir Humphry Davy in 1808 using electrolysis.
Davy had built a very large 600-plate battery which he used to pass electricity through salts.
He mixed magnesium oxide to a paste with (probably) strontium sulfate. He made a depression in the paste and placed mercury metal there to act as an electrode. Platinum was used as a counter electrode.
When electricity was passed through the paste, a strontium-mercury amalgam formed at the mercury electrode.
Davy removed the mercury from the amalgam by heating it to leave strontium metal. (1),(2).
The element was named strontium by Davy after the mineral it was produced from.
Davy discovered or isolated for the first time many alkali and alkali earth metals including potassium, sodium, barium, calcium and magnesium.
Appearance & Characteristics
Strontium metal burns in air with a distinctive red flame, forming a mixture of strontium oxide and nitride.
The world's most accurate atomic clock, based on strontium atoms, would neither gain nor lose a second in more than 200 million years.
Harmful effects:
Strontium's non-radioactive isotopes are considered non-toxic.
As a result of its chemical similarity to its fellow Group 2 element, calcium, strontium replaces and mimics calcium in the human body. Absorption of the radioactive isotope 90Sr, distributed due to fallout from nuclear tests, can lead to various bone disorders and diseases.
Characteristics:
Strontium is a soft, silvery metal. When cut it quickly turns a yellowish color due to the formation of strontium oxide (strontia, SrO) . Finely powdered strontium metal is sufficiently reactive to ignite spontaneously in air.
It reacts with water quickly (but not violently like the Group 1 metals) to produce strontium hydroxide and hydrogen gas.
Strontium and its compounds burn with a crimson flame and are used in fireworks.
Strontium is used for producing glass (cathode ray tubes) for color televisions. It is also used in producing ferrite ceramic magnets and in refining zinc.
The world's most accurate atomic clock, accurate to one second in 200 million years, has been developed using strontium atoms.
Strontium salts are used in flares and fireworks for a crimson color.
Strontium chloride is used in toothpaste for sensitive teeth.
Strontium oxide is used to improve the quality of pottery glazes.
The isotope 90Sr is one of the best long-lived, high-energy beta emitters known. It is used in cancer therapy.
Strontium's non-radioactive isotopes are considered non-toxic.
As a result of its chemical similarity to its fellow Group 2 element, calcium, strontium replaces and mimics calcium in the human body. Absorption of the radioactive isotope 90Sr, distributed due to fallout from nuclear tests, can lead to various bone disorders and diseases.
Characteristics:
Strontium is a soft, silvery metal. When cut it quickly turns a yellowish color due to the formation of strontium oxide (strontia, SrO) . Finely powdered strontium metal is sufficiently reactive to ignite spontaneously in air.
It reacts with water quickly (but not violently like the Group 1 metals) to produce strontium hydroxide and hydrogen gas.
Strontium and its compounds burn with a crimson flame and are used in fireworks.
Uses of Strontium
Strontium is used for producing glass (cathode ray tubes) for color televisions. It is also used in producing ferrite ceramic magnets and in refining zinc.
The world's most accurate atomic clock, accurate to one second in 200 million years, has been developed using strontium atoms.
Strontium salts are used in flares and fireworks for a crimson color.
Strontium chloride is used in toothpaste for sensitive teeth.
Strontium oxide is used to improve the quality of pottery glazes.
The isotope 90Sr is one of the best long-lived, high-energy beta emitters known. It is used in cancer therapy.
Abundance & Isotopes
Abundance earth's crust: 370 parts per million by weight, 87 parts per million by moles
Abundance solar system: 50 parts per billion by weight, 0.7 parts per billion by moles
Cost, pure: $100 per 100g
Cost, bulk: $ per 100g
Source: Strontium is never found free in nature. The principal strontium ores are celestine (strontium sulfate, SrSO4) and strontianite (strontium carbonate, SrCO3). The main commercial process for strontium metal production is reduction of strontium oxide with aluminum.
Isotopes: Strontium has 28 isotopes whose half-lives are known, with mass numbers 75 to 102. Of these, four are stable: 84Sr, 86Sr, 87Sr and 88Sr. 88Sr is the most abundant in nature at 82.6%.
Abundance solar system: 50 parts per billion by weight, 0.7 parts per billion by moles
Cost, pure: $100 per 100g
Cost, bulk: $ per 100g
Source: Strontium is never found free in nature. The principal strontium ores are celestine (strontium sulfate, SrSO4) and strontianite (strontium carbonate, SrCO3). The main commercial process for strontium metal production is reduction of strontium oxide with aluminum.
Isotopes: Strontium has 28 isotopes whose half-lives are known, with mass numbers 75 to 102. Of these, four are stable: 84Sr, 86Sr, 87Sr and 88Sr. 88Sr is the most abundant in nature at 82.6%.
Energies
Specific heat capacity: 0.30 J g-1 K-1
Heat of fusion: 8.30 kJ mol-1
1st ionization energy: 549.5 kJ mol-1
3rd ionization energy: 4138 kJ mol-1
Heat of fusion: 8.30 kJ mol-1
1st ionization energy: 549.5 kJ mol-1
3rd ionization energy: 4138 kJ mol-1
Heat of atomization: 164 kJ mol-1
Heat of vaporization : 144.0 kJ mol-1
2nd ionization energy: 1064.2 kJ mol-1
Electron affinity: 5 kJ mol-1
Heat of vaporization : 144.0 kJ mol-1
2nd ionization energy: 1064.2 kJ mol-1
Electron affinity: 5 kJ mol-1
Oxidation & Electrons
Shells: 2,8,18,8,2
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 0.95
Minimum oxidation number: 0
Min. common oxidation no.: 0
Electronegativity (Pauling Scale): 0.95
Electron configuration: [Kr] 5s2
Maximum oxidation number: 2
Max. common oxidation no.: 2
Polarizability volume: 27.6 Å3
Maximum oxidation number: 2
Max. common oxidation no.: 2
Polarizability volume: 27.6 Å3
Reactions & Compounds
Reaction with air: vigorous, ⇒ SrO, Sr2N3
Reaction with 15 M HNO3: vigorous, ⇒ H2, Sr(NO3)2
Oxide(s): SrO, SrO2 (strontium peroxide)
Hydride(s): SrH2
Reaction with 15 M HNO3: vigorous, ⇒ H2, Sr(NO3)2
Oxide(s): SrO, SrO2 (strontium peroxide)
Hydride(s): SrH2
Reaction with 6 M HCl: vigorous, ⇒ H2, SrCl2
Reaction with 6 M NaOH: vigorous, ⇒ none
Chloride(s): SrCl2
Reaction with 6 M NaOH: vigorous, ⇒ none
Chloride(s): SrCl2
Radius
Atomic radius: 215 pm
Ionic radius (2+ ion): 132 pm
Ionic radius (2- ion): pm
Ionic radius (2+ ion): 132 pm
Ionic radius (2- ion): pm
Ionic radius (1+ ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Ionic radius (3+ ion): pm
Ionic radius (1- ion): pm
Conductivity
Thermal conductivity: 35.4 W m-1 K-1
Electrical conductivity: 5 x 106 S m-1
References
1. Mary Elvira Weeks, Discovery of the Elements., Journal of Chemical Education (June 1932) p1046.
2. T. K. Kenyon, Science and Celebrity: Humphry Davy's Rising Star., Chemical Heritage Magazine, (2008/9 edition).
2. T. K. Kenyon, Science and Celebrity: Humphry Davy's Rising Star., Chemical Heritage Magazine, (2008/9 edition).
Cite this Page
For online linking, please copy and paste one of the following:
<a href="http://www.chemicool.com/elements/strontium.html">Strontium</a>or
<a href="http://www.chemicool.com/elements/strontium.html">Strontium Element Facts</a>To cite this page in an academic document, please use the following MLA compliant citation:
"Strontium." Chemicool Periodic Table. Chemicool.com. 24 Feb. 2011. Web. <http://www.chemicool.com/elements/strontium.html>.