Isotopes of molybdenum
Open-knowledge reference entry

Molybdenum (42Mo) has seven isotopes in nature, with atomic masses of 92, 94-98, and 100. All are stable except 100Mo, which undergoes double beta decay with a half-life of 7.07×1018 years (the shortest known for this mode) to 100Ru. 92Mo and 98Mo are also energetically able to decay in this manner, to zirconium and ruthenium respectively; the others are theoretically stable. There are also a total of 32 synthetic isotopes known, and at least 13 metastable nuclear isomers, ranging in atomic mass from 81 to 119.
The isotopes with mass 93 or lower decay by electron capture or positron emission to niobium isotopes (or zirconium after delayed proton emission); those with mass 99 or higher by ordinary beta decay to technetium. The most stable of the former are 93Mo, recently measured to have a half-life around 4800 years, and 90Mo at 5.56 hours. The most stable of the latter is the medically important 99Mo, half-life 65.932 hours, and whose decay leads to the chief isotope of technetium. By far the most stable isomer is 93m1Mo at 6.85 hours, decaying to its ground state.
List of isotopes
Molybdenum-99
Molybdenum-99 is produced commercially by intense neutron-bombardment (i.e. fission) of a highly purified uranium-235 target, followed rapidly by extraction.
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