103Rh

103Rh is a stable isotope of the chemical element rhodium (Rh, atomic number 45). It has a mass number of 103 and is the only stable isotope of rhodium. Natural rhodium is essentially monoisotopic, consisting almost entirely of 103Rh.

Because it is stable, 103Rh does not decay and has an effectively infinite half-life in nature. Other rhodium isotopes exist only as radioisotopes produced in laboratories or reactors for research, and they decay with various half-lives.

Rhodium's primary industrial applications include catalysts, particularly in automotive catalytic converters, and corrosion-resistant coatings and jewelry plating. The presence of 103Rh as the stable isotope underpins the elemental abundance and quality of natural rhodium; in research settings, isotopic analyses and calibration often reference natural rhodium, which is dominated by 103Rh.