<page_title> Isotopes of mercury </page_title> <section_title> List of isotopes </section_title> <table> <cell> 194Hg <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 444(77) y <col_header> half-life </col_header> </cell> <cell> 203Hg <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> </table>
The longest-living isotopes are ¹⁹⁴Hg with a half-life of 444 years, and ²⁰³Hg.