Helion (chemistry)
A helion (symbol h) is the 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 decay of tritium, an isotope of hydrogen:
CODATA reports the mass of a helion particle as mh = 5.0064127862(16)×10−27 kg[1] = 3.014932246932(74) Da.[2]
Helions are intermediate products in the proton–proton chain reaction in stellar fusion.
An antihelion is the antiparticle of a helion, consisting of two antiprotons and an antineutron.
References
[edit]- ^ "2022 CODATA Value: helion mass". The NIST Reference on Constants, Units, and Uncertainty. NIST. May 2024. Retrieved 2024-05-18.
- ^ "2022 CODATA Value: helion mass in u". The NIST Reference on Constants, Units, and Uncertainty. NIST. May 2024. Retrieved 2024-05-18.
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