samarium-147

chemical isotope

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July 13, 2026

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Samarium-147 is a naturally occurring isotope of samarium, a rare-earth metal. While samarium-144, -150, -152, and -154 are stable, samarium-147 is one of the three naturally occurring isotopes that are alpha emitters. Samarium-147 has a very long half-life of 7 x 10¹⁵ years. This isotope is utilized in the samarium-neodymium dating method, a technique used in geochronology to determine the ages of geologic materials. This method relies on the radioactive decay of samarium-147 into neodymium-143. Samarium itself is a silvery-white metal, relatively stable in air, and is found in various rare-earth minerals.12

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samarium
1 percent), samarium-147 (15.0 percent), samarium-148 (11.2 percent), samarium-149 (13.8 percent), samarium-150 (7.4 percent), samarium-152 (26.8 percent), and samarium-154 (22.0 percent). Samarium-144, samarium-150, samarium-152, and samarium-154 are stable, but the other three naturally occurring isotopes are alpha emitters. A total of 34 (excluding nuclear isomers)
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1 percent), samarium-147 (15.0 percent), samarium-148 (11.2 percent), samarium-149 (13.8 percent), samarium-150 (7.4 percent), samarium-152 (26.8 percent), and samarium-154 (22.0 percent). Samarium-144, samarium-150, samarium-152, and samarium-154 are stable, but the other three naturally occurring isotopes are alpha emitters. A total of 34 (excluding nuclear isomers)
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dating
Samarium–neodymium method
The radioactive decay of samarium of mass 147 (¹⁴⁷Sm) to neodymium of mass 143 (¹⁴³Nd) has been shown to be capable of providing useful isochron ages for certain geologic materials. Both parent and daughter belong to the rare-earth element group, which is itself the subject of numerous geologic investigations.…
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The radioactive decay of samarium of mass 147 (¹⁴⁷Sm) to neodymium of mass 143 (¹⁴³Nd) has been shown to be capable of providing useful isochron ages for certain geologic materials. Both parent and daughter belong to the rare-earth element group, which is itself the subject of numerous geologic investigations.…
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Earth
Accretion of the early Earth
…it decays, or those of samarium-147 and its decay product neodymium-143, indicate that the oldest meteorites formed some 4.56 billion years ago. Other isotope studies demonstrate that Earth formed within, at most, a few tens of millions of years after the birth of the Sun.
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…it decays, or those of samarium-147 and its decay product neodymium-143, indicate that the oldest meteorites formed some 4.56 billion years ago. Other isotope studies demonstrate that Earth formed within, at most, a few tens of millions of years after the birth of the Sun.
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