samarium


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Related to samarium: europium, samarium oxide

samarium

(səmâr`ēəm), metallic chemical element; symbol Sm; at. no. 62; at. wt. 150.36; m.p. 1,072°C;; b.p. 1,791°C;; sp. gr. 7.54 at 20°C;; valence +2 or +3. Samarium is a lustrous silver-white metal. It is one of the rare-earth metalsrare-earth metals,
in chemistry, group of metals including those of the lanthanide series and actinide series and usually yttrium, sometimes scandium and thorium, and rarely zirconium. Promethium, which is not found in nature, is not usually considered a rare-earth metal.
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 of the lanthanide serieslanthanide series,
a series of metallic elements, included in the rare-earth metals, in Group 3 of the periodic table. Members of the series are often called lanthanides, although lanthanum (atomic number 57) is not always considered a member of the series.
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 in Group 3 of the periodic tableperiodic table,
chart of the elements arranged according to the periodic law discovered by Dmitri I. Mendeleev and revised by Henry G. J. Moseley. In the periodic table the elements are arranged in columns and rows according to increasing atomic number (see the table entitled
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. It has two crystalline forms (see allotropyallotropy
[Gr.,=other form]. A chemical element is said to exhibit allotropy when it occurs in two or more forms in the same physical state; the forms are called allotropes.
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). The metal does not oxidize at room temperature but ignites when heated above 150°C;. Samarium is found widely distributed in nature; it is obtained commercially from the minerals monazitemonazite
, yellow to reddish-brown natural phosphate of the rare earths, mainly the cerium and lanthanum metals, usually with some thorium. Yttrium, calcium, iron, and silica are frequently present.
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 and bastnasite. Naturally occurring samarium is a mixture of seven isotopes, three of which are radioactive with extremely long half-lives. The metal was not isolated in relatively pure form until recently, although it has long been used in pyrophoric alloys used in cigarette lighter flints. Samarium is used as a catalyst in certain organic reactions. A samarium-cobalt compound, SmCo5, is used to make magnets for use in computer memories. The oxide, samaria, is used in special infrared absorbing glass and cores of carbon arc-lamp electrodes. Since one isotope of samarium is a good neutron absorber, the element has found use in nuclear reactor control rods. Samarium was discovered in 1879 by P. E. Lecoq de Boisbaudran by spectroscopic analysis of the mineral samarskite.

samarium

[sə′mar·ē·əm]
(chemistry)
A rare-earth metal, atomic number 62, symbol Sm; melts at 1350°C, tarnishes in air, ignites at 200-400°C.

samarium

a silvery metallic element of the lanthanide series occurring chiefly in monazite and bastnaesite and used in carbon-arc lighting, as a doping agent in laser crystals, and as a neutron-absorber. Symbol: Sm; atomic no.: 62; atomic wt.: 150.36; valency: 2 or 3; relative density: 7.520; melting pt.: 1074°C; boiling pt.: 1794°C
References in periodicals archive ?
2 2011-2016 Global Cost and Profit of Samarium Industry
37) Equally important are plans to resume the mining of fresh ore having an approximate 12 percent content of neodymium and samarium.
At present, Congress should classify neodymium and samarium as strategic minerals for the next 5 to 10 years, adding them to the NDS, while the domestic supply chain for permanent magnets is reestablished.
The economic benefits of mining for rare earth minerals are dependent on the concentrations of the various rare earth elements: light rare earth minerals (neodymium, lanthanum, cerium, praesodymium), heavy rare earth minerals (yttrium, dysprosium, terbium, holmium, erbium, thulium, ytterbium, lutetium), and medium rare earth minerals (europium, samarium, and gadolinium), since this has an impact on the cost of refining the rare earth minerals and the degree to which there is demand for these various types of elements.
But Lamoreaux points out that both assumptions about the temperature of the Oklo reactor and the ratio of samarium isotopes were accepted in previous Oklo studies.
signal is defined as the specific signal obtained, and noise is defined as the nonspecific signal of the PCR background control, which is the reaction without DNA template) for the aminated primers was substantially higher, especially with the samarium labeled [beta]-actin-specific probe detection.
Samarium 153-lexidronam has also undergone large-scale controlled testing in the United States and Europe (Collins et al.
Noteworthy are the use of improved helix support materials, in particular boron nitride and diamond with improved thermal conductivity; progress in helix circuit design, in particular the velocity taper which improved efficiency; superior magnetic material in the form of samarium cobalt; and finally the use of dispenser cathodes.
In the same year, Lecoq de Boisbaudran, who had discovered gallium (see 1874), identified a new rare earth element, which he named samarium, because he had found it in a mineral called samarskite, which, in turn, bore the name of an otherwise obscure Russian mining engineer named Samarski.
Other rate earth hexaboride materials, including praseodymium hexaboride and samarium hexaboride, have been investigated as thermionic emitters, but his research has been minimal, says Christman.
USPRwire, Mon Aug 01 2016] The 'Global and Chinese Samarium Nitrate Industry, 2011-2021 Market Research Report' is the detailed comprehensive analysis of the current state of the global Samarium Nitrate industry with a focus on the Chinese market.