Samarium

=**Samarium**= Is a chemical element with the symbol **Sm**, atomic number 62 and atomic weight 150.36. It is a moderately hard silvery metal which readily oxidizes in air. Being a typical member of the lanthanide s, samarium usually assumes the oxidation state +3. The last compound is a common reducing agent in chemical synthesis. Samarium has no significant biological role and is only slightly toxic. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth's crust and is more common than such metals as tin. Samarium occurs with concentration up to 2.8% in several minerals including cerite, gadolinite, samarskite, monazite, and bastnasite, the last two being the most common commercial sources of the element. These minerals are mostly found in China, the USA, Brazil, India, Sri Lanka, and Australia; China is by far the world leader in samarium mining and production. The major commercial 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, without losing their magnetic properties. Radioactive isotopes samrium-153 is the major component of the drug samarium (153Sm) lexidronam (Quadramet) 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 important factors considered in the reactor design and operation. Other applications of samarium include catalysis of chemical reactions, radioactive dating, and an X-ray laser.


 * Samarium** has a bright silver lustre and is reasonably stable in air. It ignites in air at 150°C. It is a rare earth metal. It is found with other rare earth elements in minerals including monazite and bastnaesite and is used in electronics industries.

Discovery of Samarium
Author: Dr. Doug Stewart In 1853 chemist Jean Charles Galissard de Marignac discovered samarium when he found lines in mineral spectra he was studying that matched no known element. Paul-Émile Lecoq de Boisbaudran isolated a samarium salt in 1879. First, Boisbaudran extracted 'didymium' from the mineral samarskite and made a solution of 'didymium' nitrate. He then added ammonium hydroxide and found two precipitates were formed; one containing 'didymium' and the other a new element - samarium. We should bear in mind that 'didymium' had been incorrectly identified as a new element by Carl Mosander in 1841. 'Didymium' was even given the symbol Di in Mendeleev's first edition of the periodic table in 1869. It wasn't until 1885 that Carl Auer von Welsbach established that 'didymium' was actually composed of two distinct, new elements: neodymium and praseodymium. The new element samarium was named after the mineral samarskite in which it had been found. (The mineral samarskite had been named in 1847 by mineralogist Heinrich Rose after a Russian mine official, Vasili Samarsky-Bykhovets, who had given him a sample of it.) In addition to samarium, Lecoq discovered gallium in 1875 and he went on to isolate gadolinium in 1885 and dysprosium in 1886. In 1901 Eugène-Antole Demarçay found that Lecoq's samarium was impure and he successfully isolated europium magnesium nitrate from a sample of samarium magnesium nitrate.


 * Name:** Samarium
 * Symbol:** Sm
 * Atomic Number:** 62
 * Atomic Mass:** 150.36 amu
 * Melting Point:** 1072.0 °C (1345.15 K, 1961.6 °F)
 * Boiling Point:** 1900.0 °C (2173.15 K, 3452.0 °F)
 * Number of Protons/Electrons:** 62
 * Number of Neutrons:** 88
 * Crystal Structure:** Rhombohedral
 * Density @ 293 K:** 7.54 g/cm3
 * Color:** silver


 * Date of Discovery:** 1879
 * Discoverer:** Paul Emile Lecoq de Boisbaudran
 * Name Origin:** smarskite (mineral)
 * Uses:** used in magnets, in alloys with cobalt, and nuclear reactors
 * Obtained From:** found with other rare earths



Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Sm-144 || Stable ||
 * Sm-145 || 340.0 days ||
 * Sm-146 || 1.03E8 years ||
 * Sm-147 || 1.06E11 years ||
 * Sm-148 || 7.0E15 years ||
 * Sm-149 || Stable ||
 * Sm-150 || Stable ||
 * Sm-151 || 90.0 years ||
 * Sm-152 || Stable ||
 * Sm-153 || 1.92 days ||
 * Sm-154 || Stable ||