Isotopes of cadmium
Naturally occurring cadmium is composed of 8 isotopes. For two of them, natural radioactivity has been observed, and three others are predicted to possibly decay though this has not been observed; it may be presumed the half-lives are extremely long. The two natural radioactive isotopes are and . The other three are, , and ; only lower limits on their decays have been set. Only three isotopes—,, and —are theoretically stable. Among the isotopes absent in natural cadmium, the most long-lived are with a half-life of 461.3 days, and with a half-life of 53.46 hours. All of the remaining radioactive isotopes have half-lives that are less than 7 hours and the majority of these are less than 5 minutes. This element also has 12 known meta states, with the most stable being , and .
The known isotopes of cadmium range from to. The primary decay mode before the stable isotope is electron capture to isotopes of silver, and after, beta emission to isotopes of indium.
A 2021 study has shown at high ionic strengths, cadmium isotope fractionation mainly depends on its complexation with carboxylic sites. At low ionic strengths, nonspecific cadmium binding induced by electrostatic attractions plays a dominant role and promotes cadmium isotope fractionation during complexation.
List of isotopes
Cadmium-113m
Cadmium-113m is a cadmium radioisotope and nuclear isomer with a half-life of 13.9 years. In a normal thermal reactor, it has a very low fission product yield, plus its large neutron capture cross section means that most of even the small amount produced is destroyed in the course of the nuclear fuel's burnup; thus, this isotope is not a significant contributor to nuclear waste.Fast fission or fission of some heavier actinides will produce at higher yields.