{"id":41,"date":"2020-04-08T14:58:07","date_gmt":"2020-04-08T14:58:07","guid":{"rendered":"https:\/\/thechemicalelements.com\/?page_id=41"},"modified":"2023-08-16T10:37:54","modified_gmt":"2023-08-16T10:37:54","slug":"strontium","status":"publish","type":"post","link":"https:\/\/thechemicalelements.com\/strontium\/","title":{"rendered":"Strontium (Sr)"},"content":{"rendered":"\n

Strontium is a chemical element with atomic number 38 in the periodic table. It\u2019s the 15<\/span>th<\/span> most plentiful metal found in Earth\u2019s crust with 0.034% ppm natural occurrence. Being a member of the alkaline earth metals group of the periodic table, this <\/span>lithophile<\/span> metallic element has two valence electrons present in the outermost shell. <\/span><\/p>\n\n\n\n

Strontium is a trace mineral whose function resembles the one of calcium<\/a> in the human body. The strontium-90 radioisotope is one of the most frequently found radioactive forms in the debris left after a nuclear catastrophe or nuclear fission. In addition, strontium salts are colored in a bright red color which is popularly used for emergency lights and fireworks. <\/span><\/p>\n\n\n\n

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Chemical and Physical Properties of Strontium<\/span><\/h3>\n\n\n\n
Property<\/strong><\/td>Value<\/strong><\/td><\/tr>
The symbol in the periodic table of elements<\/td>Sr<\/td><\/tr>
Atomic number<\/td>38<\/td><\/tr>
Atomic weight (mass)<\/td>87.62 g.mol-1<\/td><\/tr>
Group number<\/td>2 (Alkaline earth metals)<\/td><\/tr>
Period<\/td>5 (s-block)<\/td><\/tr>
Color<\/td>Pale yellow color with a silvery luster<\/td><\/tr>
Physical state<\/td>Solid at room temperature<\/td><\/tr>
Half-life<\/td>From less than 25 milliseconds to 28.9 years<\/td><\/tr>
Electronegativity according to Pauling<\/td>1<\/td><\/tr>
Density<\/td>2.6 g.cm-3 at 20\u00b0C<\/td><\/tr>
Melting point<\/td>777\u00b0C, 1431\u00b0F, 1050 K<\/td><\/tr>
Boiling point<\/td>1377\u00b0C, 2511\u00b0F, 1650 K<\/td><\/tr>
Van der Waals radius<\/td>0.215 nm<\/td><\/tr>
Ionic radius<\/td>0.113 nm (+2)<\/td><\/tr>
Isotopes<\/td>35<\/td><\/tr>
Most characteristic isotope<\/td>86Sr, 87Sr, 88Sr<\/td><\/tr>
Electronic shell<\/td>[Kr] 5s2<\/td><\/tr>
The energy of the first ionization<\/td>549.2 kJ.mol-1<\/td><\/tr>
The energy of the second ionization<\/td>1064 kJ.mol-1<\/td><\/tr>
Discovery date<\/td>In 1790 by Adair Crawford and William Cruickshank<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

With the periodic table symbol Sr, atomic number 38, atomic mass of 87.62 g.mol<\/span>-1<\/span>, and electron configuration  [Kr] 5s<\/span>2<\/span>, strontium is a soft, yellow alkaline-earth metal with a silvery luster. It reaches its boiling point at 1377\u00b0C, 2511\u00b0F, 1650 K, while the melting point is achieved at 777\u00b0C, 1431\u00b0F, 1050 K. This member of the alkaline earth metals family of elements in the periodic table has an electronegativity of 1.0 according to Pauling, whereas the atomic radius according to van der Waals is 0.215 nm. <\/span><\/p>\n\n\n\n

This silvery metal has a high refractive index and burns with a distinctive red color flame. When dissolved in liquid ammonia, it forms a dark blue solution. Strontium metal occurs in three crystalline allotropic forms with transition points at 235\u00b0C and 540\u00b0C. It\u2019s softer than calcium and harder than barium.  <\/span><\/p>\n\n\n\n

Being an alkaline earth metal, strontium tarnishes rapidly upon exposure to air and produces volatile reactions when it comes into contact with H2O. Due to this reason, strontium must be isolated and kept away from both air and water when stored.<\/span><\/p>\n\n\n\n

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How Was Strontium Discovered?<\/span><\/h3>\n\n\n\n

When the Irish chemist and physician Adair Crawford (1748 \u2013 1795) first attempted to determine the specific heats of the gaseous elements, he conducted a series of experiments. During his scientific work, his attention was caught by a mineral sample obtained from a lead mine near the small town of Strontian in Argyll, Scotland. <\/span><\/p>\n\n\n\n

At that time, his fellow colleagues were considering beryllium<\/a> and strontium as the same element. They had labeled the mineral \u2018<\/span>strontites<\/span><\/i>\u2019, while its oxides were known as \u2018<\/span>strontia<\/span><\/i>\u2019. Crawford had a reserved opinion on what was labeled as barium carbonate. He and his fellow colleague William Cruickshank held the belief that the new mineral was, in fact, a completely different and new substance. <\/span><\/p>\n\n\n\n

In 1790 Crawford and Cruickshank succeeded in providing scientific proof for their claims, by which they became the first discoverers of element 38 – strontium (Sr).<\/span><\/p>\n\n\n\n

All chemicals that have been derived from alkaline earth elements were isolated in their pure form by Sir Humphry Davy. In 1808 he managed to obtain the pure forms of magnesium<\/a>, calcium, strontium, and barium<\/a>, by applying the method of electrolysis. He had previously used electrolysis with great success in the purification process of the elements potassium and sodium<\/a>.<\/span><\/p>\n\n\n\n

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How Did Strontium Get Its Name?<\/span><\/h3>\n\n\n\n

Strontium is named after a Scottish village called Strontian.<\/span><\/p>\n\n\n\n

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Where Can You Find Strontium?<\/span><\/h3>\n\n\n\n

Strontium is the 15<\/span>th<\/span> most commonly occurring chemical element in Earth\u2019s crust, but it\u2019s never found free in nature. The naturally occurring forms of element 38 can be traced in sediments, rocks, water, air, and soil. <\/span><\/p>\n\n\n\n

Element 38 can always be found in natural water systems. Since this substance is highly soluble in water, it is released to groundwater as those minerals dissolve. The main natural sources of strontium are the minerals <\/span>putnisite<\/span><\/i> (SrCa\u2084Cr\u2088\u00b3\u207a(CO\u2083)\u2088(SO\u2084)(OH)\u2081\u2086\u00b725 H\u2082O), <\/span>celestite <\/span><\/i>(SrSO<\/span>4<\/span>), and the carbonate <\/span>strontianite<\/span><\/i> (SrCO<\/span>3<\/span>). <\/span><\/p>\n\n\n\n

Strontium metal is typically prepared by electrolysis of the fused chloride that is mixed with potassium<\/a> chloride. Also, it can be prepared by reduction of strontium oxide with aluminium<\/a> in a vacuum. After this, the resulting substance is exposed at a temperature in order to produce pure strontium by the distillation process.<\/span><\/p>\n\n\n\n

The world\u2019s leading commercial producer of strontium is China, while the biggest strontium mines are located in the UK, Turkey, Mexico, and Spain. Annually, more than 140,000 tons of strontium are mined worldwide.<\/span><\/p>\n\n\n\n

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List of Strontium Minerals<\/span><\/h3>\n\n\n\n

The following is a list of minerals from which strontium can be obtained by mining:<\/span><\/p>\n\n\n\n