Isotopes of Silver

Isotopes Of Silver

Naturally occurring silver (Ag) is composed of the two stable isotopes 107Ag and 109Ag with 107Ag being the more abundant (51.839% natural abundance). Standard atomic mass: 107.8682(2) u. Twenty-eight radioisotopes have been characterized with the most stable being 105Ag with a half-life of 41.29 days, 111Ag with a half-life of 7.45 days, and 112Ag with a half-life of 3.13 hours.

All of the remaining radioactive isotopes have half-lives that are less than an hour and the majority of these have half-lives that are less than 3 minutes. This element has numerous meta states with the most stable being 108mAg (t_* 418 years), 110mAg (t_* 249.79 days) and 106mAg (t_* 8.28 days).

Isotopes of silver range in atomic weight from 92.950 u (93Ag) to 129.950 u (130Ag). The primary decay mode before the most abundant stable isotope, 107Ag, is electron capture and the primary mode after is beta decay. The primary decay products before 107Ag are palladium (element 46) isotopes and the primary products after are cadmium (element 48) isotopes.

The palladium isotope 107Pd decays by beta emission to 107Ag with a half-life of 6.5 million years. Iron meteorites are the only objects with a high enough palladium/silver ratio to yield measurable variations in 107Ag abundance. Radiogenic 107Ag was first discovered in the Santa Clara meteorite in 1978.

The discoverers suggest that the coalescence and differentiation of iron-cored small planets may have occurred 10 million years after a nucleosynthetic event. 107Pd versus 107Ag correlations observed in bodies, which have clearly been melted since the accretion of the solar system, must reflect the presence of live short-lived nuclides in the early solar system.

Standard atomic mass: 107.8682(2) u