Page "Cadmium" Paragraph 6

Naturally occurring cadmium is composed of 8 isotopes.

Two of them are naturally radioactive, and three are expected to decay but have not been experimentally confirmed to do so.

The two natural radioactive isotopes are < sup > 113 </ sup > Cd ( beta decay, half-life is 7. 7 × 10 < sup > 15 </ sup > years ) and < sup > 116 </ sup > Cd ( two-neutrino double beta decay, half-life is 2. 9 × 10 < sup > 19 </ sup > years ).

The other three are < sup > 106 </ sup > Cd, < sup > 108 </ sup > Cd ( both double electron capture ), and < sup > 114 </ sup > Cd ( double beta decay ); only lower limits on their half-life times have been set.

At least three isotopes – < sup > 110 </ sup > Cd, < sup > 111 </ sup > Cd, and < sup > 112 </ sup > Cd – are stable.

Among the isotopes that do not occur naturally, the most long-lived are < sup > 109 </ sup > Cd with a half-life of 462. 6 days, and < sup > 115 </ sup > Cd with a half-life of 53. 46 hours.

All of the remaining radioactive isotopes have half-lives that are less than 2. 5 hours, and the majority of these have half-lives that are less than 5 minutes.

Cadmium has 8 known meta states, with the most stable being < sup > 113m </ sup > Cd ( t < sub > ½ </ sub >