Isotopes of seaborgium

Seaborgium (₁₀₆Sg) is a synthetic element and so has no stable isotopes. A standard atomic weight cannot be given. The first isotope to be synthesized was ²⁶³Sg in 1974. There are fourteen known radioisotopes from ²⁵⁷Sg to ²⁷¹Sg (except ²⁷⁰Sg) and five known isomers (^259mSg, ^261mSg, ^263mSg, ^265mSg, and ^267mSg). The longest-lived isotopes are ²⁶⁹Sg with a half-life of 13 minutes and ²⁶⁷Sg with a half-life of 9.8 minutes. Due to a low number of measurements, and the consequent overlapping measurement uncertainties at the confidence level corresponding to one standard deviation, a definite assignment of the most stable isotope cannot be made.