Cerium Isotopes

Naturally occurring cerium (58Ce) is composed of 4 stable isotopes: 136Ce, 138Ce, 140Ce, and 142Ce, with 140Ce being the most abundant (88.45% natural abundance) and the only one that is theoretically stable. The others, 136Ce, 138Ce, and 142Ce are predicted to undergo double beta decay, which has never been observed. There are 35 radioisotopes that have been characterized, with the most stable being 144Ce, with a half-life of 284.89 days; 139Ce, with a half-life of 137.64 days and 141Ce, with a half-life of 32.505 days. All of the remaining radioactive isotopes have half-lives that are less than 4 days and the majority of these have half-lives that are less than 10 minutes. The known isotopes of cerium range from 117Ce to 160Ce, in addition to 14 meta states.