Isotopes of rhodium

Naturally occurring rhodium (₄₅Rh) is composed of only one stable isotope, Rh. The most stable radioisotopes are Rh with a half-life of 4.07 years, Rh with a half-life of 207 days, and Rh with a half-life of 16.1 days. Thirty other radioisotopes have been characterized ranging from Rh to Rh - these have half-lives that are less than an hour except Rh (20.8 hours) and Rh (35.34 hours). There are also numerous meta states with the most stable being Rh with a half-life of 3.74 years and Rh with a half-life of 4.34 days.

The primary decay mode before the only stable isotope, Rh, is electron capture to ruthenium isotopes, and the primary mode after is beta emission to palladium isotopes. Mass numbers 102 and 104 are capable of decay in either sense.