Write about Samarium atom.

     

Samarium is a chemical element with the symbol Sm and atomic number 62.  It is a moderately hard silvery metal that slowly oxidizes in air.  Being a typical member of the lanthanide series, samarium usually assumes the oxidation state +3.

     Compounds of samarium(II) are also known, most notably the monoxide SmO, monochalcogenides SmS, SmSe and Sm Te, as well as samarium(II) iodide.  The last compounds is a common reducing agent in chemical synthesis.  Samarium has no significant biological role but is only slightly toxic.   Samarium was discovered in 1879 by the French chemist Paul-Emile Lecoq de Boisbudran and named after the mineral samarskite from which it was isolated.  The mineral itself was earlier named after a Russian mine official, Colonel Vassili Samarsky-Bykhovets, who thereby became the first person to have a chemical element named after him, albeit indirectly.  

     The major commercical application of samarium is in samarium-cobalt magnets, which have permanent magnetization second only to neodymium magnets;  however, samarium compounds can withstand significantly higher temperatures, above 700 C(1,292 F), without losing their magnetic properties, due to the alloys higher Curie point.  The radioactive isotope Smarium-153 is the active component of the drug samarium lexidronam, which kills cancer cells in the treatment of lung cancer, prostate cancer, breast cancer and osteosarcoma.

     Another isotope, samarium-149 is a strong neutron absorber and is therefore added to the control rods of nuclear reactors.  It is also formed as a decay product during the reactor operation and is one of the ismportant factors considered in the reactor design and operation.  other applications of samarium include catalysis of chemical reactions, radioactive dating and X-ray lasers.