Silver-109

Main isotopes of silver

iso NA half-life DM DE (MeV) DP 105Ag syn 41.2 d ε – 105Pd γ 0.344, 0.280, 0.644, 0.443 – 106mAg syn 8.28 d ε – 106Pd γ 0.511, 0.717, 1.045, 0.450 – 107Ag 51.839% is stable with 60 neutrons 108mAg syn 418 y ε – 108Pd IT 0.109 108Ag γ 0.433, 0.614, 0.722 – 109Ag 48.161% is stable with 62 neutrons 111Ag syn 7.45 d β− 1.036, 0.694 111Cd γ 0.342 –
Standard atomic weight (Ar)	107.8682(2)

Naturally occurring silver (₄₇Ag) is composed of the two stable isotopes ¹⁰⁷Ag and ¹⁰⁹Ag with ¹⁰⁷Ag being the more abundant (51.839% natural abundance). 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.

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