Iron-56

Iron-56, ⁵⁶Fe
General
Symbol	56Fe
Names	iron-56, 56Fe, Fe-56
Protons (Z)	26
Neutrons (N)	30
Nuclide data
Natural abundance	91.754%
Isotope mass	55.9349375(7) Da
Spin	0+
Excess energy	−60601.003±1.354 keV
Binding energy	492253.892±1.356 keV
	Isotopes of iron ; Complete table of nuclides

Iron-56 (⁵⁶Fe) is the most common isotope of iron. About 91.754% of all iron is iron-56.

Of all nuclides, iron-56 has the lowest mass per nucleon. With 8.8 MeV binding energy per nucleon, iron-56 is one of the most tightly bound nuclei.^[1]

The high nuclear binding energy for ⁵⁶Fe represents the point where further nuclear reactions become energetically unfavorable. Because of this, it is among the heaviest elements formed in stellar nucleosynthesis reactions in massive stars. These reactions fuse lighter elements like magnesium, silicon, and sulfur to form heavier elements. Among the heavier elements formed is ⁵⁶Ni, which subsequently decays to ⁵⁶Co and then ⁵⁶Fe.

^ Nuclear Binding Energy

[1] Nuclear Binding Energy

[1]

General
Symbol	⁵⁶Fe
Names	iron-56, 56Fe, Fe-56
Protons (Z)	26
Neutrons (N)	30
Nuclide data
Natural abundance	91.754%
Isotope mass	55.9349375(7) Da
Spin	0+
Excess energy	−60601.003±1.354 keV
Binding energy	492253.892±1.356 keV
Isotopes of iron Complete table of nuclides