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samarium n. 一種稀有金屬元素,符號Sm,原子序為62 一種稀有金屬元素,符號Sm,原子序為62 samarium n 1: a grey lustrous metallic element of the rare earth group; is used in special alloys; occurs in monazite and bastnasite [synonym: {samarium}, {Sm}, {atomic number 62}] Samarium \Sa*ma"ri*um\, n. [NL., fr. E. samarskite.] (Chem.) A rare metallic element of doubtful identity. [1913 Webster] Note: Samarium was discovered, by means of spectrum analysis, in certain minerals (samarskite, cerite, etc.), in which it is associated with other elements of the earthy group. It has been confounded with the doubtful elements decipium, philippium, etc., and is possibly a complex mixture of elements not as yet clearly identified. Symbol Sm. Provisional atomic weight 150.2. [1913 Webster] samarium
Symbol: Sm Atomic number: 62 Atomic weight: 150.35 Soft silvery metallic element, belongs to the lanthanoids. Seven natural isotopes, Sm-147 is the only radioisotope, and has a half-life of 2.5*10^11 years. Used for making special alloys needed in the production of nuclear reactors. Also used as a neutron absorber. Small quantities of samarium oxide is used in special optical glasses. The largest use of the element is its ferromagnetic alloy which produces permanent magnets that are five times stronger than magnets produced by any other material. Discovered by Francois Lecoq de Boisbaudran in 1879.
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