Fe58

Fe-58, written as 58Fe, is a stable isotope of iron. It has 26 protons and 32 neutrons, giving it a mass number of 58. Its atomic mass is about 57.94 atomic mass units. Among natural iron, 58Fe is relatively rare, contributing roughly 0.28% of iron atoms. It is one of four stable iron isotopes, the others being 54Fe, 56Fe, and 57Fe, with 56Fe being the most abundant.

Nuclear properties of 58Fe reflect that it is an even-even nucleus (both proton and neutron numbers are even), and its ground-state nuclear spin is 0+. This makes 58Fe inert to many forms of nuclear magnetic interactions and implies a highly stable configuration.

Formation and occurrence: 58Fe is produced in stellar nucleosynthesis, primarily through neutron capture processes in massive stars and in supernovae. Its presence in solar system matter results from the history of nucleosynthesis and subsequent mixing of stellar debris into the solar nebula. In rocks, minerals, and meteorites, the 58Fe/56Fe ratio can carry information about the astrophysical processes that contributed material to the early solar system.

Applications and analysis: Because it is a stable, minor constituent of iron, 58Fe is measured mainly in geochemical and cosmochemical studies to understand isotopic fractionation and nucleosynthetic signatures. Isotopic ratios involving 58Fe, such as 58Fe/54Fe or 58Fe/56Fe, are obtained using high-precision mass spectrometry. In other analytical techniques, 58Fe does not play a primary role, as Mössbauer spectroscopy typically relies on 57Fe transitions.