They have been reported as intermediates in Barbier-type reactions. Organostrontium compounds contain one or more strontium–carbon bonds. The large size of strontium and barium plays a significant part in stabilising strontium complexes with polydentate macrocyclic ligands such as crown ethers: for example, while 18-crown-6 forms relatively weak complexes with calcium and the alkali metals, its strontium and barium complexes are much stronger. The Sr 2+ ion is quite large, so that high coordination numbers are the rule. ĭue to the large size of the heavy s-block elements, including strontium, a vast range of coordination numbers is known, from 2, 3, or 4 all the way to 22 or 24 in SrCd 11 and SrZn 13. All four dihalides of strontium are known. Strontium hydroxide, Sr(OH) 2, is a strong base, though it is not as strong as the hydroxides of barium or the alkali metals. Besides the simple oxide SrO, the peroxide SrO 2 can be made by direct oxidation of strontium metal under a high pressure of oxygen, and there is some evidence for a yellow superoxide Sr(O 2) 2. Strontium metal burns in air to produce both strontium oxide and strontium nitride, but since it does not react with nitrogen below 380 ☌, at room temperature it forms only the oxide spontaneously. Strontium is intermediate between calcium and barium in its reactivity toward water, with which it reacts on contact to produce strontium hydroxide and hydrogen gas. The standard electrode potential for the Sr 2+/Sr couple is −2.89 V, approximately midway between those of the Ca 2+/Ca (−2.84 V) and Ba 2+/Ba (−2.92 V) couples, and close to those of the neighboring alkali metals. Three allotropes of metallic strontium exist, with transition points at 235 and 540 ☌. The density of strontium (2.64 g/cm 3) is similarly intermediate between those of calcium (1.54 g/cm 3) and barium (3.594 g/cm 3). Its melting (777 ☌) and boiling (1377 ☌) points are lower than those of calcium (842 ☌ and 1484 ☌ respectively) barium continues this downward trend in the melting point (727 ☌), but not in the boiling point (1900 ☌). It is softer than calcium and harder than barium. Strontium is a divalent silvery metal with a pale yellow tint whose properties are mostly intermediate between and similar to those of its group neighbors calcium and barium. Natural stable strontium, on the other hand, is not hazardous to health.Ĭharacteristics Oxidized dendritic strontium While natural strontium (which is mostly the isotope strontium-88) is stable, the synthetic strontium-90 is radioactive and is one of the most dangerous components of nuclear fallout, as strontium is absorbed by the body in a similar manner to calcium. With the replacement of cathode-ray tubes with other display methods, consumption of strontium has dramatically declined. At the peak of production of television cathode-ray tubes, as much as 75% of strontium consumption in the United States was used for the faceplate glass. During the 19th century, strontium was mostly used in the production of sugar from sugar beets (see strontian process). Strontium was first isolated as a metal in 1808 by Humphry Davy using the then newly discovered process of electrolysis. It occurs naturally mainly in the minerals celestine and strontianite, and is mostly mined from these.īoth 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 has physical and chemical properties similar to those of its two vertical neighbors in the periodic table, calcium and barium. The metal forms a dark oxide layer when it is exposed to air. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. Strontium is a chemical element it has symbol Sr and atomic number 38.
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