Noun
English Wikipedia has an article on:iron-56Wikipedia
iron-56 (uncountable)
(physics) The major stable isotope of iron, 26Fe, having 26 protons and 30 neutrons; it amounts to about 92% of the element in nature
Iron-56 has the highest, making it the most stable. Source: Internet
Iron-56 is particularly common, since it is the most stable element that can easily be made from alpha particles (being a product of decay of radioactive nickel-56, ultimately made from 14 helium nuclei). Source: Internet
The formation of nuclei with masses up to Iron-56 releases energy, while forming those that are heavier requires energy input. Source: Internet