Helion (chemistry)

A helion (symbol h) is a short name for the naked nucleus of helium, a doubly positively charged helium ion. In practice, helion refers specifically to the nucleus of the helium-3 isotope, consisting of two protons and one neutron. The nucleus of the other stable isotope of helium, helium-4 isotope, which consists of two protons and two neutrons, is specifically called an alpha particle.

This particle is emitted in the beta-minus decay of tritium, an isotope of hydrogen:

3
1H
→ 3
2He1+
 		+ 
e−
 		+ 
ν
e

According to CODATA[1], page 60, Table 33, the mass of a helion particle is mh = 5.006412700(62)×10−27 kg = 3.01493224673(12) Da.

Helions are intermediate products in the proton–proton chain reaction in stellar fusion.

References
  1. Mohr, Peter J.; Newell, David B.; Taylor, Barry N. (2016). "CODATA recommended values of the fundamental physical constants: 2014". Rev. Mod. Phys. 88 (3): 1–73. arXiv:1203.5425. doi:10.1103/RevModPhys.88.035009.


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