tritium

noun2

1. •
   A radioactive isotope of the element hydrogen (symbol T, ³H or 31H) having one proton and two neutrons.
2. •
   An atom of this isotope.

   • Electrochemical polymerization of the 1,2-tritiated monomer produced a polymer in which all of the tritiums were eliminated except for those located at the ends of the chains — 1998