100Mo

Molybdenum-100 (100Mo) is a stable isotope of the element molybdenum (atomic number 42) with a mass number of 100. It is one of the naturally occurring isotopes of molybdenum, and natural molybdenum contains about 9.6% 100Mo by abundance.

100Mo is stable and does not decay radioactively under normal conditions. It occurs in nature as part of molybdenum minerals such as molybdenite (MoS2) and other ore minerals, where it coexists with other molybdenum isotopes.

As a subject of nuclear and particle physics research, 100Mo is notable for its relatively high energy release for double beta decay to 100Ru, with a Q-value around 3 MeV. This makes it a target isotope in experiments that search for neutrinoless double beta decay, which would indicate Majorana neutrino masses and lepton-number violation. Because 100Mo is not abundantly available in pure form, experimental programs often use enriched 100Mo targets to increase sensitivity.

Enriched 100Mo is produced by isotope separation and is used in specialized research setups. In addition to its role in double beta decay studies, 100Mo serves as a reference in certain nuclear and materials science experiments and as a component in discussions of isotopic composition and nuclear properties of molybdenum. See also the broader context of molybdenum isotopes.