There are three known stable isotopes of oxygen: 16O, 17O, and 18O. Oxygen also has radioisotopes ranging from 11O to 26O. They all have short half-lives. The longest-lived radioisotope is 15O. It has a half-life of 122.24 seconds. The shortest-lived radioisotope is 12O. It has a half-life of 580(30)×10−24 seconds.