The Common Properties of the "Fertile" Isotopes

A "fertile" isotope is defined as a long-lived isotope from which, as a result of a (n,) reaction, we obtain a fissile isotope of a different element. It was found that most of the fertile isotopes have a 2Z - N = 38 value and that these isotopes are the most stable isotopes in their corresponding elements. It was also found that the largest number of "stable" nuclei have a 2Z - N = 38 "magic" value.