Table of nuclides (compact, with energy per baryon)
Site main page
Isotope table in compact form with half-lives
Isotope table in compact form with decay mode
The isotope table below shows isotopes of the chemical elements, including all with half-life of at least 3 seconds (and many with shorter, although isotopes with a neutron deficit of more than 4 aren’t listed). They are arranged with increasing atomic numbers (proton numbers) from upper left to lower right and increasing neutron numbers from lower left to upper right for each proton number.
Cell color denotes the energy per baryon of each isotope. Energy is calculated assuming the Bohr model (that is, with a quadratic progression for kinetic energy) subtracting the energy of the electrons from the energy of the isotope to give the energy of the nucleus. Since at least 98% of the energy of the electrons is mass energy until at least Darmstadium, this is a sufficient approximation for this purpose. If you’ve scrolled so the color legend is not in view, allowing your cursor to dwell over a cell will cause a pop-up text box to indicate that isotope’s energy and half-life. If a cell has an isomer, dwelling over it will also disclose the half-life of the most stable nuclear isomer state.
A black border is added to the isotope with the lowest energy per baryon for an element. An orange border is added for the isotope with the lowest energy per baryon for an element with the opposite parity as the overall lowest (normally, the lowest energy for an isotope with an odd number of neutrons), and a white border is added for the lowest energy per baryon currently known where it is NOT the lowest overall. The lowest energy for a baryon count overall has a blue band (so Cerium 140 has a blue band as it is the lowest energy isotope with 140 baryons, but Cerium 134 has the black band since it has the least per baryon among the isotopes of Cerium). Long lasting isotopes with z of 2 less than a blue-banded isotope get a green band. On ties (+/- 1 KeV), both isotopes have a narrower border added. The isotope with the lowest energy per baryon for the row has its element id in bold. Color is generally a smooth progression from bright purple for the highest energy through pink, red, brown, gray, green, and blue at the lowest energy. But to clarify context, green is interrupted by a yellow band (from bright yellow at the lowest energy to pale yellow at the highest) and red is interrupted by a light green band. Uncertainty is typically under 500 eV, larger uncertainties noted, those over 5 KeV have element shown in italics. It should be noted, lowest energy is not equivalent to most stable. Pu238 has the least energy among the 238 baryon counts, but U238 is most stable. In some cases the lowest energy nucleus can absorb an electron and become a more stable case (Ca41 for instance). At the right edge of the table, approaching the Dirac limit, the cells are colored with a darkening grey to warn of the natural limit. It is unlikely nuclei with a z above 132 can exist for very long.