Top of Page By Morgan, an eigth grader at Mill Valley Middle School, Mill Valley, CA

Properties The Discoverer Uses Isotopes Commercial Production Glossary Bibliography

"It only attracts the best!"

Properties Symbol Sm Atomic Number 62 Atomic Weight 150.36 Melting Point 1074 ºc Boiling Point 1794 ºc Oxidation States +2,+3 Density 7.52 g/cc @300K Samarium, which is classified as a rare earth metal, is slivery and reactive. The atomic number is also the number of protons in the nucleus and the number of electons on the outside. To figure out how many neutrons there are, subtract the atomic number from the atomic weight. For Samarium there are 88 electrons in its atoms. Inside of the atom there are "shells" in which a certain number of electrons go. Each "shell" has a different number of electrons which will fit. A Samarium atom would have 2 electons in the first shell, 8 electrons in the second, and so on. The number of electrons in the outermost shell are the valence electrons. Valence electrons tell about the reactivity of the element. Since samarium only has two electrons in the outermost shell it is very reactive, meaning that it can easly find a substance to bond with. Samarium is unusual because it has two oxidation states: +2 and +3. Back to Top

The Discoverer Samarium was discovered in 1879 by Lecoq de Boibaudran. Boisbaudran was a French scientist, who, in his lifetime discovered three other elements besides samarium. Samarium, which is pronounced (seh-MER-i-em), is named in honor of Russian mine official, Colnel Samarski. Samarium is almost never found uncombined in nature. It is most often found in monazite sand, which can be found in great proportions in Florida, India, and Brazil. Though it is also found in the minerals samarskite and bastnasite. Samarium is ranked fifth on the abundance chart for rare earth metals found in the earth's crust. Back to Top

Uses Samarium is used in the ceramic and electronic industries, as well as in luminescent and infrared absorbing glasses. It is also used in carbon-arc lighting in the motion picture industry. Samarium can also be used as an absorber in nuclear reacters and in compond with cobalt becomes a superimagnet. Interestingly enough it is also used in headphones and small speakers. Back to Top

Isotopes There are twenty known isotopes of samarium and it is one of few elements that have so man stable isotopes that are naturally occuring. Most naturally occuring samarium is a mixture of several isotopes. Of the twenty isotopes, there are only four which do not have a half-life. The highest natural abundance of an isotope just happens to be a non-radioactive one. The half lives of samarium's isotopes last from 9.5 seconds to 7 times 10^15 years! Back to Top

Commercial Production Most commercial grade samarium is found in monazite sand. Unwanted metals can be removed from finely ground monazite by magnetic or flotation processes. Then there are two steps to obtain samarium metal. First, it reacts with eother flouride or chloride forming Samariumflouride (SmF ) or Samariumchloride (SmCl ). Then to get samarium metal either of the two compounds is reduced by calcium metal or lithium metal. In both cases the samarium halide and active metal, the calcium or lithium, is loaded into a tantalum crucible and then fired in a helium atmosphere. Because the densities of the active metal and the halide are different, they settle out when cooled. Then you just have to cut the samarium metal away from the impurities. Commercially it costs $5/g of samarium. Back to Top

Glossary carbon-arc lighting: high power lights used in the motion picture industry. electron: a negatively charged particle on the outside of an atom's nucelus. half-life: the amount of time it takes for half of the nuclei matter to decay. halide: a natural compound that, in this case it is the compound containing the samarium. isotope: atoms of the ssame element that have diiferent numbers of nuetrons. neutron: a particle in the nucleus that has no charged. oxidation: is the number of electrons an atom gains or loses when combined with anther atom. proton: a positively charged particle in the nucelus. tantalum crucible: a type of modern technique for separating pure rare earth metals. valence electrons: the number of electrons in the outer shell of an atom. Back to Top

Bibliography Chemicool Periodic Table Environmental Chemistry Periodic Table Interactive Periodic Table of the Elements Periodic Table Periodic Table of the Elements Pictorial Periodic Table Web Elements Periodic Table Pictures found: http://www.pnl.gov/er_news/ 2_97/mag-sb.htm http://www.chemicalelements.com/ elements/sm.html http://www.site.ifrance.com/okapi/ samarium.htm Back to Top