Naturally occurring manganese is composed of one stable isotope, 55Mn. Several radioisotopes have been isolated and described, ranging in atomic weight from 46 u (46Mn) to 72 u (72Mn). The most stable are 53Mn with a half-life of 3.7 million years, 54Mn with a half-life of 312.2 days, and 52Mn with a half-life of 5.591 days. All of the remaining radioactive isotopes have half-lives of less than three hours, and the majority of less than one minute. The primary decay mode in isotopes lighter than the most abundant stable isotope, 55Mn, is electron capture and the primary mode in heavier isotopes is beta decay. Manganese also has three meta states.
Naturally occurring manganese is composed of one stable isotope 55Mn Several radioisotopes have been isolated and described ranging in atomic weight from 46 u (46Mn) to 72 u (72Mn) The most stable are 53Mn with a half-life of 37 million years 54Mn with a half-life of 3122 days and 52Mn with a half-life of 5591 days All of the remaining radioactive isotopes have half-lives of less than three hours and the majority of less than one minute The primary decay mode in isotopes lighter than the most abundant stable isotope 55Mn is electron capture and the primary mode in heavier isotopes is beta decay Manganese also has three meta states