Isotopes of lanthanum

Naturally occurring lanthanum (₅₇La) is composed of one stable (La) and one radioactive (La) isotope, with the stable isotope, La, being the most abundant (99.911% natural abundance). There are 39 radioisotopes that have been characterized, with the most stable being La, with a half-life of 1.03×10 years; La, with a half-life of 60,000 years and La, with a half-life of 40.289 hours. The remaining radioactive isotopes have half-lives that are less than a day and the majority of these less than a minute. This element also has 12 nuclear isomers, the longest-lived of which is La, with a half-life of 24.3 minutes. Lighter isotopes mostly decay to isotopes of barium and heavy ones mostly decay to isotopes of cerium. La can decay to both.

The known isotopes of lanthanum range from La to La.