Agent Name

Samarium

CAS Number

7440-19-9

Formula

Sm

Major Category

Metals

Category

Rare Earth Metals

Description

A hard, silver-white metal [Argonne] Tarnishes on exposure to air; Melting point = 1074 degrees C; [Merck Index]

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]

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" and linked occupational diseases.

Reference Link

LANL: Samarium

Adverse Effects
Fibrogenic

Yes

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