Ir193

Iridium-193 (Ir-193) is a stable isotope of the element iridium, characterized by a mass number of 193. It has 77 protons in its nucleus and, accordingly, 116 neutrons. Ir-193 is one of two stable isotopes of iridium, the other being Ir-191.

In nature, iridium is found as a mixture of stable isotopes, with Ir-193 accounting for roughly the majority of natural iridium. The two stable isotopes, Ir-191 and Ir-193, together comprise essentially all naturally occurring iridium, with Ir-193 contributing about 63 percent of the total and Ir-191 about 37 percent. The remaining isotopes of iridium are far rarer and not naturally abundant.

Because Ir-193 is stable, it does not undergo radioactive decay and has no finite half-life under normal conditions. Its stability, like that of natural iridium, is a consequence of the nuclear binding in heavy elements. While Ir-192 is the isotope commonly used in industrial radiography and cancer therapy, Ir-193 itself has limited direct radiological applications due to its lack of radioactivity. Nonetheless, stable isotopes such as Ir-193 are useful as reference standards in analytical techniques such as mass spectrometry and isotopic tracing.

See also: Iridium, Isotopes of iridium.