Rhodium-100

Main isotopes of rhodium

Iso­tope Decay abun­dance half-life mode energy (MeV) pro­duct 99Rh syn 16.1 d ε – 99Ru γ 0.089, 0.353, 0.528 – 101mRh syn 4.34 d ε – 101Ru IT 0.157 101Rh γ 0.306, 0.545 – 101Rh syn 3.3 y ε – 101Ru γ 0.127, 0.198, 0.325 – 102mRh syn 3.7 y ε – 102Ru γ 0.475, 0.631, 0.697, 1.046 – 102Rh syn 207 d ε – 102Ru β+ 0.826, 1.301 102Ru β− 1.151 102Pd γ 0.475, 0.628 – 103Rh 100% is stable with 58 neutrons 105Rh syn 35.36 h β− 0.247, 0.260, 0.566 105Pd γ 0.306, 0.318 –
Standard atomic weight (Ar)	7002102905500000000♠102.90550(2)

Naturally occurring rhodium (₄₅Rh) is composed of only one stable isotope, ¹⁰³Rh. The most stable radioisotopes are ¹⁰¹Rh with a half-life of 3.3 years, ¹⁰²Rh with a half-life of 207 days, and ⁹⁹Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized with atomic weights ranging from 88.949 u (⁸⁹Rh) to 121.943 u (¹²²Rh). Most of these have half-lifes that are less than an hour except ¹⁰⁰Rh (half-life: 20.8 hours) and ¹⁰⁵Rh (half-life: 35.36 hours). There are also numerous meta states with the most stable being ^102mRh (0.141 MeV) with a half-life of about 3.7 years and ^101mRh (0.157 MeV) with a half-life of 4.34 days.

The primary decay mode before the only stable isotope, ¹⁰³Rh, is electron capture and the primary mode after is beta emission. The primary decay product before ¹⁰³Rh is ruthenium and the primary product after is palladium.

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