Science Fair Project Encyclopedia
Exotic helium isotopes
Exotic helium isotopes are the unstable isotopes of helium. A subset of exotic light nuclei , these synthetic radioactive isotopes have larger atomic weights than helium's natural isotopes, helium-3 and helium-4.
Although all exotic helium isotopes decay with a half-life of less than one second, researchers have eagerly created exotic light isotopes though particle accelerator collisions to create unusual atomic nuclei for elements such as helium, lithium, and nitrogen. The bizarre nuclear structures of such isotopes may offer insight into the isolated properties of neutrons.
The most widely-studied exotic helium isotope, for example, is helium-8. This isotope is thought to consist of a normal helium-4 nucleus surrounded by four neutrons dubbed a "halo." Halo nuclei have become an area of intense research. Isotopes up to helium-10, with two protons and eight neutrons, have been confirmed. By comparison, the most common 4He isotope has only two neutrons.
Table of exotic helium isotopes
|Helium-5||none||helium-4||7.6 × 10−22||highly unstable|
|lithium-6||0.8067||decomposes through beta decay|
|Helium-7||none||helium-6||2.9 × 10−21||highly unstable|
|Helium-9||none||helium-8||1.5 × 10−21||highly unstable|
|Helium-10||none||helium-9||2.7 × 10−21||highly unstable|
- General Tables — abstracts for helium and other exotic light nuclei
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