<page_title> Isotopes of tellurium </page_title> <section_title> List of isotopes </section_title> <table> <cell> 121Te <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 19.16(5) d <col_header> half-life </col_header> </cell> </table>
The longest-lived isotope of tellurium is ¹²¹Te with a half-life of nearly 19 days.