Manganese has a total of 25 known isotopes. Isotopes of an element have the same number of protons but different numbers of neutrons in their atomic nuclei, resulting in variations in their atomic mass. Among the 25 known isotopes of manganese, the most stable and common are:
- Manganese-55 (55Mn) is the most abundant and stable isotope of manganese, making up about 100% of natural manganese.
- Manganese-54 (54Mn) is a radioactive isotope with a half-life of around 312.2 days.
- Manganese-56 (56Mn) is also a radioactive isotope with a half-life of approximately 2.6 hours.
The other isotopes of manganese have relatively short half-lives and are primarily produced through artificial or synthetic means in laboratories or nuclear reactions.