Sb72

Sb72 refers to the isotope of the element antimony (chemical symbol Sb) with mass number 72. With atomic number Z = 51, its neutron number would be N = A − Z = 21. This places Sb72 among highly proton-rich, light-mass isotopes.

Sb72 is not known to exist as a bound nucleus. In contemporary nuclear mass models, isotopes with such a low neutron-to-proton ratio for antimony are predicted to lie beyond the proton drip line, meaning they would be unbound and decay rapidly if formed. As a result, there is no confirmed experimental observation of Sb72, and its properties (such as a measured half-life or exact decay channels) are not established.

If Sb72 were momentarily produced, its primary decay modes would be governed by its proton-rich character. Likely pathways include proton emission to a lighter nucleus (for Sb72, potentially to Te71) and, depending on energy considerations, beta-plus decay or electron capture to neighboring nuclei (for example, to Te72). The competition between proton emission and beta decays would depend on the specific nuclear structure and energy balance of the state formed.

In summary, Sb72 is the unobserved, highly proton-rich isotope of antimony with mass number 72. It is treated in nuclear theory as unbound or extremely short-lived, illustrating the challenges of reaching and characterizing nuclei far from the valley of stability.