138Ce

Cerium-138 (138Ce) is a stable isotope of the element cerium (chemical symbol Ce) with atomic number 58. It has 58 protons and 80 neutrons. In nature, 138Ce occurs as one of the natural cerium isotopes, but it is present at a far lower abundance than the most common isotopes of cerium.

As a stable, even-even nucleus, 138Ce does not undergo radioactive decay under normal conditions, and it has no measured half-life. Its stability makes it a part of the isotopic composition used in geochemical and cosmochemical studies, where precise measurements of cerium isotopes help in tracing geological processes and planetary formation.

Natural occurrence and abundance: cerium in nature exists as a mixture of isotopes, with 138Ce representing a trace component alongside other stable isotopes such as 136Ce and 140Ce. The exact natural abundance of 138Ce varies among samples and is typically described as a minor constituent of natural cerium.

Nuclear data and methods: 138Ce is identified and quantified using high-precision mass spectrometry and related analytical techniques that resolve isotopic ratios. Such measurements contribute to isotopic reference systems and to understanding the geochemical behavior of rare earth elements.

Applications: isotopic compositions of cerium, including 138Ce, are used in geochemistry, cosmochemistry, and geochronology to study rock formation, planetary differentiation, and environmental tracing. While not a primary target in industrial applications, accurate knowledge of cerium isotopes supports a range of scientific investigations.

See also: Cerium isotopes, Isotope information pages, Geochemistry of rare earth elements.