| Agent Name |
Samarium |
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| CAS Number |
7440-19-9 |
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| Formula |
Sm |
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| Major Category |
Metals |
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| Category |
Rare Earth Metals |
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| Description |
A hard, silver-white metal [Argonne] Tarnishes on exposure to air; Melting point = 1074 degrees C; [Merck Index] |
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| Sources/Uses |
Used in control rods in nuclear reactors; Also used in alloys with cobalt to make strong permanent magnets; Occurs naturally along with other rare earth metals in the minerals monazite, bastnaesite, samarskite, cerite, orthite, ytterbite, and fluorspar; [Merck Index] There are 7 naturally-occurring isotopes with 3 of them being weakly radioactive with extremely long half-lives. There are 2 man-made radionuclides with long enough half-lives to be of concern as environmental contaminants. Sm-146 and Sm-151 are produced during nuclear fission of uranium and plutonium and have half-lives of 100,000,000 years and 90 years respectively. Used as a catalyst in organic chemistry, a pyrophoric metal in lighter flints, and a core in carbon arc-lamp electrodes; [Argonne] |
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| Comments |
Most Important Radionuclide: Sm-151
Source: Fission product of uranium and plutonium;
Half-Life: 90 years
Specific Activity: 27 Ci/g
Decay Mode: Beta
GI Absorption: 0.05%
Lung Clearance Half-Time: Weeks
Internal Toxicity: High
Annual Limit on Intake: 0.1 mCi
Average Radiation Energy (MeV): Beta 0.020; Gamma <0.001; [Argonne]
[See Glossary for references.] See "Radiation, ionizing." See "RARE EARTH METALS."
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| Reference Link |
http://periodic.lanl.gov/elements/62.html |
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| Links to Other NLM Databases |
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| Health Studies |
Human Health Effects from Hazardous Substances Data Bank: IONIZING RADIATION
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