Isotopes of rhenium

Main isotopes of rhenium

Iso­tope Decay abun­dance half-life mode energy (MeV) pro­duct 185Re 37.4% is stable with 110 neutrons 187Re 62.6% 4.12×1010 y β− 0.0026 187Os
Standard atomic weight (Ar)	186.207(1)

Naturally occurring rhenium (₇₅Re) is 37.4% ¹⁸⁵Re, which is stable, and 62.6% ¹⁸⁷Re, which is unstable but has a very long half-life (41.2×10⁹ years). Among elements with a known stable isotope, only indium and tellurium similarly occur with a stable isotope in lower abundance than the long-lived radioactive isotope.

There are 33 other unstable isotopes recognized, the longest-lived of which are ¹⁸³Re with a half-life of 70 days, ¹⁸⁴Re with a half-life of 38 days, ¹⁸⁶Re with a half-life of 3.7186 days, ¹⁸²Re with a half-life of 64.0 hours, and ¹⁸⁹Re with a half-life of 24.3 hours. There are also numerous isomers, the longest-lived of which are ^186mRe with a half-life of 200,000 years and ^184mRe with a half-life of 169 days. All others have half-lives less than a day.

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