| While bismuth was traditionally regarded as the element with the heaviest stable isotope, bismuth-209, it had long been suspected
to be unstable on theoretical grounds. This was finally demonstrated in 2003 when researchers at the Institut d'Astrophysique
Spatiale in Orsay, France, measured the alpha emission half-llife of 209Bi to be 1.9 x 1019 years, over a billion times longer than the current estimated age of the universe. Owing to its extraordinarily long half-llife, for nearly all applications bismuth can be treated as if it is stable and non-radioactive. The radioactivity is of academic
interest, however, because bismuth is one of few elements whose radioactivity was suspected, and indeed theoretically predicted,
before being detected in the laboratory.
|
Notes
Notable Isotopes 
207Bi [124 neutrons]
Abundance: synthetic