On the periodic table’s light-element corner, beryllium sits between lithium and boron and shows up in fields from materials science to cosmogenic nuclide studies. Its isotopes, though few, carry outsized importance for dating, nuclear data, and radiation safety.
There are 10 Beryllium Isotopes, ranging from Be-10 to Be-9. For each isotope you’ll find below data organized as Mass number (A),Half-life (s or y),Decay mode to make comparisons of stability and decay straightforward — see the list you’ll find below.
Which beryllium isotope is stable?
Be-9 is the only stable, naturally occurring isotope of beryllium; the others are radioactive, with Be-10 notable for its long half-life and production by cosmic-ray spallation, which makes it useful for geological and atmospheric studies.
How is Be-10 used in practice?
Be-10 is widely used as a tracer and exposure-age dating tool: deposited in soils and sediments by cosmic rays, its measured concentration helps estimate surface exposure times, erosion rates, and past atmospheric processes.
Beryllium Isotopes
| Isotope | Mass number (A) | Half-life (s or y) | Decay mode |
|---|---|---|---|
| Be-5 | 5 | 7.00e-22 s | Proton emission to He-4 |
| Be-6 | 6 | 2.00e-21 s | Two-proton emission / breakup to helium |
| Be-7 | 7 | 4,598,000 s | Electron capture to lithium-7 |
| Be-8 | 8 | 6.70e-17 s | Breakup into two alpha particles |
| Be-9 | 9 | stable | Stable (observationally stable) |
| Be-10 | 10 | 1,390,000 y | Beta-minus to boron-10 |
| Be-11 | 11 | 13.81 s | Beta-minus to boron-11; delayed-neutron possible |
| Be-12 | 12 | 2.15e-02 s | Beta-minus; beta-delayed neutron emission |
| Be-13 | 13 | 3.00e-22 s | Neutron emission (unbound resonance) |
| Be-14 | 14 | 4.35e-03 s | Beta-minus; possible beta-delayed neutron emission |
Images and Descriptions
Be-5
An extremely short-lived, proton-rich resonance seen in accelerator experiments. It promptly breaks apart (proton or alpha emission) and does not occur naturally. Studies of Be-5 help map the proton drip line and nuclear forces in light systems.
Be-6
A very unstable, proton-rich isotope that decays almost instantly by two-proton emission or breakup into helium fragments. It is produced in nuclear reactions and used experimentally to probe correlations between protons and short-range nuclear interactions.
Be-7
A radioactive isotope with a 53-day half-life used in astrophysics and environmental tracing. It decays by electron capture to lithium-7 and is produced by cosmic-rays in the atmosphere and in accelerator experiments for calibration and reaction studies.
Be-8
An extremely short-lived resonance that splits into two alpha particles in less than a femtosecond. Its transient existence is central to stellar nucleosynthesis (triple-alpha process) and nuclear structure studies of clustered light nuclei.
Be-9
The only stable and naturally abundant beryllium isotope, accounting for essentially all terrestrial beryllium. It is widely used in materials, metallurgy, and nuclear research as a target, neutron source, and probe of nuclear structure.
Be-10
A cosmogenic radioisotope with a 1.39-million-year half-life used for surface exposure and sediment dating. Produced by cosmic-ray spallation in the atmosphere and rocks, it decays by beta emission to boron-10 and helps study erosion and climate history.
Be-11
A well-known one-neutron halo nucleus with an extended neutron distribution and a half-life of about 13.8 seconds. It beta-decays to boron-11 and serves as a benchmark for studying weakly bound systems and halo structure in light nuclei.
Be-12
A neutron-rich isotope with a brief half-life that decays by beta emission and sometimes neutron emission. Produced in fragmentation reactions, Be-12 helps probe shell evolution and changes in nuclear structure far from stability in light systems.
Be-13
A very neutron-rich, unbound resonance observed in experiments; it rapidly emits a neutron and breaks into lighter fragments. Be-13 provides information about neutron correlations and the location of the neutron drip line for beryllium isotopes.
Be-14
One of the most neutron-rich bound beryllium isotopes with a short millisecond-scale half-life; it beta-decays and may emit delayed neutrons. Be-14 exhibits strong neutron correlations and has been studied as a candidate two-neutron halo nucleus.
