page_title: Strontium
section_title: Applications
hierarchical_section_title: Strontium / Applications
caption_attribution_description: Viewsonic CRT computer monitor.
context_page_description: Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is exposed to air. Strontium has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these.
  Both strontium and strontianite are named after Strontian, a village in Scotland near which the mineral was discovered in 1790 by Adair Crawford and William Cruickshank; it was identified as a new element the next year from its crimson-red flame test color. Strontium was first isolated as a metal in 1808 by Humphry Davy using the then newly-discovered process of electrolysis. During the 19th century, strontium was mostly used in the production of sugar from sugar beet. At the peak of production of television cathode ray tubes, as much as 75 percent of strontium consumption in the United States was used for the faceplate glass.
context_section_description: Consuming 75% of production, the primary use for strontium was in glass for colour television cathode ray tubes, where it prevented X-ray emission. This application for strontium has been declining because CRTs are being replaced by other display methods. This decline has a significant influence on the mining and refining of strontium. All parts of the CRT must absorb X-rays. In the neck and the funnel of the tube, lead glass is used for this purpose, but this type of glass shows a browning effect due to the interaction of the X-rays with the glass. Therefore, the front panel is made from a different glass mixture with strontium and barium to absorb the X-rays. The average values for the glass mixture determined for a recycling study in 2005 is 8.5% strontium oxide and 10% barium oxide.
  Because strontium is so similar to calcium, it is incorporated in the bone. All four stable isotopes are incorporated, in roughly the same proportions they are found in nature. However, the actual distribution of the isotopes tends to vary greatly from one geographical location to another. Thus, analyzing the bone of an individual can help determine the region it came from. This approach helps to identify the ancient migration patterns and the origin of commingled human remains in battlefield burial sites.
  ⁸⁷Sr/⁸⁶Sr ratios are commonly used to determine the likely provenance areas of sediment in natural systems, especially in marine and fluvial environments. Dasch (1969) showed that surface sediments of Atlantic displayed ⁸⁷Sr/⁸⁶Sr ratios that could be regarded as bulk averages of the ⁸⁷Sr/⁸⁶Sr ratios of geological terranes from adjacent landmasses. A good example of a fluvial-marine system to which Sr isotope provenance studies have been successfully employed is the River Nile-Mediterranean system. Due to the differing ages of the rocks that constitute the majority of the Blue and White Nile, catchment areas of the changing provenance of sediment reaching the River Nile delta and East Mediterranean Sea can be discerned through strontium isotopic studies. Such changes are climatically controlled in the Late Quaternary.
  More recently, ⁸⁷Sr/⁸⁶Sr ratios have also been used to determine the source of ancient archaeological materials such as timbers and corn in Chaco Canyon, New Mexico. ⁸⁷Sr/⁸⁶Sr ratios in teeth may also be used to track animal migrations.
  Strontium aluminate is frequently used in glow in the dark toys, as it is chemically and biologically inert.
  Strontium carbonate and other strontium salts are added to fireworks to give a deep red colour. This same effect identifies strontium cations in the flame test. Fireworks consume about 5% of the world's production. Strontium carbonate is used in the manufacturing of hard ferrite magnets.
  Strontium chloride is sometimes used in toothpastes for sensitive teeth. One popular brand includes 10% total strontium chloride hexahydrate by weight. Small amounts are used in the refining of zinc to remove small amounts of lead impurities. The metal itself has a limited use as a getter, to remove unwanted gases in vacuums by reacting with them, although barium may also be used for this purpose.
  The ultra-narrow optical transition between the [Kr]5s₂ ¹S₀ electronic ground state and the metastable [Kr]5s5p ³P₀ excited state of ⁸⁷Sr is one of the leading candidates for the future re-definition of the second in terms of an optical transition as opposed to the current definition derived from a microwave transition between different hyperfine ground states of ¹³³Cs. Current optical atomic clocks operating on this transition already surpass the precision and accuracy of the current definition of the second.
caption: Cathodic monitor front panel made from strontium and barium oxide-containing glass. This application used to consume most of the world's production of strontium.
exif: {}