<page_title> Isotopes of argon </page_title> <section_title> List of isotopes </section_title> <table> <cell> 37Ar <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 35.04(4) d <col_header> half-life </col_header> </cell> <cell> 39Ar <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 269(3) y <col_header> half-life </col_header> </cell> <cell> 42Ar <col_header> nuclide symbol </col_header> <col_header> excitation energy </col_header> </cell> <cell> 32.9(11) y <col_header> half-life </col_header> </cell> </table>
The isotopes are ³⁹Ar with a half-life of 269 years, ⁴²Ar with a half-life of 32.9 years, and ³⁷Ar with a half-life of 35.04 days.