Isotopes of Barium

Isotopes Of Barium

Naturally occurring barium (Ba) is a mix of six stable isotopes and one very long-lived radioactive primordial isotope, barium-130, recently identified as being unstable by geochemical means (from analysis of the presence of its daughter xenon-130 in rocks). This nuclide decays by double-electron capture (absorbing two electrons and emitting two neutrinos) with a half-life of (0.5-2.7)×1021 years (about 1011 times the age of the universe). Barium-132 is observed to be unstable but its half-life is unknown, so it's still a "stable" isotope now. The other five (from 134Ba to 138Ba) are theoretically stable.

There are a total of thirty-three known radioisotopes in addition to 130Ba, but most of these are highly radioactive with half-lives in the several millisecond to several minute range. and thus never encountered in nature. The only notable exceptions are 133Ba which has a half-life of 10.51 years, and 137mBa (2.55 minutes), which is the decay product of 137Cs (30.17 years, and a common fission product).

Barium-114 is the lightest nuclide known to undergo cluster decay, emitting a nucleus of stable 12C to produce 102Sn in .0034% of decays.

Standard atomic mass: 137.327(7) u