Isotopes of lutetium
Naturally occurring lutetium is composed of one stable isotope 175Lu and one long-lived radioisotope, 176Lu with a half-life of 3.78 × 1010 years. Thirty-four radioisotopes have been characterized, with the most stable, besides 176Lu, being 174Lu with a half-life of 3.31 years, and 173Lu with a half-life of 1.37 years. All of the remaining radioactive isotopes have half-lives that are less than 9 days, and the majority of these have half-lives that are less than half an hour. This element also has 18 meta states, with the most stable being 177mLu, 174mLu and 178mLu.
The isotopes of lutetium range in atomic weight from 149.973 to 183.961. The primary decay mode before the most abundant stable isotope, 175Lu, is electron capture, and the primary mode after is beta emission. The primary decay products before 175Lu are isotopes of ytterbium and the primary products after are isotopes of hafnium.Lutetium-177
