View source for Helion (chemistry)

{{short description|Helium-3 isotope nucleus}}
{{other uses|Helion (disambiguation)}}
A '''helion''' (symbol h) is the [[Atomic nucleus|nucleus]] of a [[helium]] atom, a doubly positively charged [[cation]]. The term ''helion'' is a [[portmanteau]] of ''helium'' and ''ion'', and in practice refers specifically to the nucleus of the [[helium-3]] isotope, consisting of two [[protons]] and one [[neutron]]. The nucleus of the other (and far more common) [[stable isotope]] of helium, [[helium-4]], consisting of two protons and two neutrons, is called an [[alpha particle]] or an alpha for short.

This particle is the daughter product in the beta-minus [[radioactive decay|decay]] of [[tritium]], an isotope of [[hydrogen]]:
: {| border="0"
|- style="height:2em;"
|{{nuclide|link=no|Hydrogen|3}}||→&nbsp;||{{nuclide|link=yes|helium|3|charge=1+}}&nbsp;||+&nbsp;||{{SubatomicParticle|link=yes|Electron}}&nbsp;||+&nbsp;||{{SubatomicParticle|link=yes|Electron Antineutrino}}
|}

[[CODATA]] reports the mass of a helion particle as {{physconst|mh|symbol=yes}} =&nbsp;{{physconst|mh_Da|after=.}}

Helions are intermediate products in the [[proton–proton chain reaction]] in [[Stellar nucleosynthesis|stellar fusion]].

An antihelion is the [[antiparticle]] of a helion, consisting of two [[antiprotons]] and an [[antineutron]].

== References ==
{{reflist}}

[[Category:Nuclear chemistry]]
[[Category:Helium]]

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