Search results
Results from the WOW.Com Content Network
Because of the way it reacts with air and water, strontium only exists in nature when combined to form minerals. Naturally occurring strontium is stable, but its synthetic isotope Sr-90 is only produced by nuclear fallout. In groundwater strontium behaves chemically much like calcium. At intermediate to acidic pH Sr 2+ is the dominant strontium ...
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.
Naturally occurring strontium is nonradioactive and nontoxic at levels normally found in the environment, but 90 Sr is a radiation hazard. [4] 90 Sr undergoes β − decay with a half-life of 28.79 years and a decay energy of 0.546 MeV distributed to an electron, an antineutrino, and the yttrium isotope 90 Y, which in turn undergoes β − decay with a half-life of 64 hours and a decay energy ...
Calcium oxalate is insoluble in water, but is soluble in mineral acids. Ca 2+ + (COO) 2 (NH 4) 2 → (COO) 2 Ca + NH 4 + Sr 2+ Strontium ions precipitate with soluble sulfate salts. Sr 2+ + Na 2 SO 4 → SrSO 4 + 2Na + All ions of alkaline earth metals form white precipitate with ammonium carbonate in the presence of ammonium chloride and ammonia.
Strontium is naturally deposited in hydroxyapatite, the mineral component of bones and teeth, following its consumption in food and water. [11] Each locale has a unique Sr isotope ratio and, therefore, the ratio found in a bone or enamel sample can be cross referenced against a record of environmental Sr ratios and assigned to a region. [11]
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.
Hints and the solution for today's Wordle on Tuesday, December 10.
Strontium titanate single crystal substrates (5x5x0.5mm). The transparent substrate (left) is pure SrTiO 3 and the black substrate is doped with 0.5% (weight) of niobium. SrTiO 3 is an excellent substrate for epitaxial growth of high-temperature superconductors and many oxide-based thin films.