![]() ![]() Strontium metal (98% pure) in January 1990 cost about $5/oz. It has been used as a gemstone, but is very soft. Strontium titanate is an interesting optical material as it has an extremely high refractive index and an optical dispersion greater than that of diamond. It has also found use in producing ferrite magnets and in refining zinc. The major use for strontium at present is in producing glass for color television picture tubes. These devices hold promise for use in space vehicles, remote weather stations, navigational buoys, etc., where a lightweight, long-lived, nuclear-electric power source is needed. This isotope is one of the best long-lived high-energy beta emitters known, and is used in SNAP (Systems for Nuclear Auxilliary Power) devices. It is a product of nuclear fallout and presents a health problem. Diagram of the nuclear composition, electron configuration, chemical data, and valence orbitals of an atom of strontium-88 (atomic number. Fast Facts: Strontium Element Name: Strontium Element Symbol: Sr Atomic Number: 38 Appearance: Silvery-white metal that oxidizes to pale yellow Group: Group 2 (Alkaline Earth Metal) Period: Period 5 Atomic Weight: 87.62 Electron Configuration: Kr 5s2 Discovery: A. Of greatest importance is 90Sr with a half-life of 29 years. Sixteen other unstable isotopes are known to exist. Natural strontium is a mixture of four stable isotopes. Volatile strontium salts impart a beautiful crimson color to flames, and these salts are used in pyrotechnics and in the production of flares. The finely divided metal ignites spontaneously in air. Freshly cut strontium has a silvery appearance, but rapidly turns a yellowish color with the formation of the oxide. It should be kept under kerosene to prevent oxidation. It does not absorb nitrogen below 380 oC. ![]() Strontium is softer than calcium and decomposes in water more vigorously. An isotope is one of two or more species of atoms of the same chemical element that have different atomic mass numbers (protons + neutrons). Since 1961 the standard unit of atomic mass has been one-twelfth the mass of an atom of the isotope carbon-12. Three allotropic forms of the metal exist, with transition points at 235 and 540 oC. That is, Atomic Weight (isotope mass) × (fractional natural abundance). atomic weight, also called relative atomic mass, ratio of the average mass of a chemical element’s atoms to some standard. The metal can be prepared by electrolysis of the fused chloride mixed with potassium chloride, or is made by reducing strontium oxide with aluminum in a vacuum at a temperature at which strontium distills off. Strontium is found chiefly as celestite and strontianite. (Strontian, town in Scotland) Isolated by Davey by electrolysis in 1808 however, Adair Crawford in 1790 recognized a new mineral (strontianite) as differing from other barium minerals. ![]()
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