Stable136Ce

Stable136Ce, formally written as Ce-136, is a stable isotope of the element cerium (atomic number 58). It has 58 protons and 78 neutrons, giving it a mass number of 136. As a stable isotope, 136Ce does not undergo radioactive decay under normal conditions and is one of the naturally occurring cerium isotopes found in terrestrial materials.

In nature, Ce-136 is present at low abundance relative to the more common cerium isotopes. Its presence contributes to the overall isotopic composition of natural cerium, which is measured in geochemical and cosmochemical studies using mass spectrometry. Because it is stable, 136Ce is useful as a reference point in isotopic analyses and in achieving high-precision measurements of cerium and related elements.

Formation and occurrence: 136Ce is produced through stellar nucleosynthesis and becomes incorporated into primitive solar-system material. In rocks and minerals, the relative proportions of cerium isotopes, including 136Ce, can be used to investigate geochemical processes such as crust-mantle differentiation and meteoritic contributions to planetary materials.

Relation to other cerium isotopes: Ce-136 is one of three stable cerium isotopes, alongside Ce-138 and Ce-140. These isotopes together comprise the vast majority of naturally occurring cerium, with 136Ce contributing a small but detectable fraction to the overall isotopic signature.

Applications: Beyond basic characterization, 136Ce is used in isotope geochemistry and cosmochemistry studies, calibration of mass spectrometric measurements, and investigations into the history of cerium in rocks and meteorites. See also Ce-138, Ce-140, and general cerium isotopes for context.