148Sm

147Sm is one of the stable isotopes of samarium, but this article concerns 148Sm, the isotope with mass number 148. It has 62 protons (the atomic number of samarium) and 86 neutrons. 148Sm is one of the seven stable isotopes of samarium and occurs naturally in trace amounts within natural samarium.

As a stable isotope, 148Sm does not undergo radioactive decay under normal conditions. Its ground-state nuclear spin is 0+, consistent with many even-even nuclei in the lanthanide series. Because it is stable, it has no half-life and is not used in radiometric dating schemes.

In nature, 148Sm is found in the same minerals that host rare earth elements, such as monazite and bastnasite. Its natural abundance is typically cited as roughly around ten percent of natural samarium, varying slightly by sample.

Applications of 148Sm are largely related to its role as a stable isotope. It is used as a reference and tracer in isotope ratio measurements, and in some analytical contexts it serves as a calibration standard for mass spectrometry and isotope-dilution techniques. Although the Sm-Nd dating system centers on the decay of 147Sm to 143Nd, the stable isotopes of samarium, including 148Sm, support geochemical and cosmochemical studies by providing fixed isotopic anchors. Related isotopes of interest include 146Sm, which is extinct, and 147Sm, which is used in dating applications.