It is usually designated by the symbol T, although you should symbolize systematically as 3H. It was discovered on 1934 by Rutherford, Oliphant and Harteck in the study of deuteron bombardment of deuterium.
Tritium in the atmosphere occurs at the rate of one atom of hydrogen per 1017, and is continuously formed in the upper atmosphere nuclear reactions induced by cosmic rays. It is industrially obtained by bombardment of lithium with low energy neutrons.
Tritium has a half life of 12.4 years and emits radiation β very low energy (0.018 MeV), totally free of γ radiation so virtually no radiotoxicity. As for the chemical properties, tritium is the exception to the general rule that radioactive isotopes of an element behave similarly to their non- radioactive forms, due to the large mass difference presenting respect to hydrogen. However, when being incorporated into heavier molecules, this difference becomes negligible, so that it is widely used in labeling molecules (tritiació), and acts as a tracer properly, especially when non-labile hydrogens replaced.
Apart from being used for energy production by nuclear fusion, is also used to a lesser extent, for the preparation of luminous paints, besides the already mentioned as tracer.
Last review: April 22, 2015