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Strontium is a chemical element; it has 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.
Celestine (the IMA-accepted name) [6] or celestite [1] [7] [a] is a mineral consisting of strontium sulfate (Sr S O 4). The mineral is named for its occasional delicate blue color. Celestine and the carbonate mineral strontianite are the principal sources of the element strontium, commonly used in fireworks and in various metal alloys.
The rubidium–strontium dating method (Rb–Sr) is a radiometric dating technique, used by scientists to determine the age of rocks and minerals from their content of specific isotopes of rubidium (87 Rb) and strontium (87 Sr, 86 Sr). One of the two naturally occurring isotopes of rubidium, 87 Rb, decays to 87 Sr with a half-life of 49.23 ...
He was also involved in the discovery or co-discovery of titanium (1795), strontium (1793), cerium (1803), and chromium (1797) and confirmed the previous discoveries of tellurium (1798) and beryllium (1798). [7] [8] Klaproth was a member and director of the Berlin Academy of Sciences. [2]
Strontium and barium have fewer applications than the lighter alkaline earth metals. Strontium carbonate is used in the manufacturing of red fireworks. [75] Pure strontium is used in the study of neurotransmitter release in neurons. [76] [77] Radioactive strontium-90 finds some use in RTGs, [78] [79] which utilize its decay heat.
The ratio 87 Sr/ 86 Sr is the parameter typically reported in geologic investigations; [4] ratios in minerals and rocks have values ranging from about 0.7 to greater than 4.0 (see rubidium–strontium dating). Because strontium has an electron configuration similar to that of calcium, it readily substitutes for calcium in minerals.
Strontium: 1787 W. Cruikshank: 1808 H. Davy W. Cruikshank in 1787 and Adair Crawford in 1790 concluded that strontianite contained a new earth. It was eventually isolated electrochemically in 1808 by Davy. [89] 5 Boron: 1787 L. Guyton de Morveau, A. Lavoisier, C. L. Berthollet, and A. de Fourcroy: 1809 H. Davy: Borax was known from ancient times.
The dates indicate the true age of the minerals only if the rocks have not been subsequently altered (see rubidium–strontium dating). [28] [29] Rubidium-82, one of the element's non-natural isotopes, is produced by electron-capture decay of strontium-82 with a half-life of 25.36 days.