helium-4

E761917

Helium-4 is the most common stable isotope of helium, consisting of two protons and two neutrons, and is a key product of both Big Bang nucleosynthesis and stellar fusion.

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Statements (50)

Predicate Object
instanceOf alpha particle
boson
helium isotope
nucleus
stable isotope
atomicNumber 2
bindingEnergyPerNucleon ≈7.07 MeV
boilingPointAt1atm ≈4.22 K
bosonicStatistics Bose–Einstein NERFINISHED
charge +2e (nucleus)
chemicalElement helium
cosmologicalMassFraction ≈0.24–0.25 of baryonic matter
discoveredAsAlphaParticleBy Ernest Rutherford NERFINISHED
dominantIsotopeOf helium
electricCharge +2 elementary charges
firstIonizationEnergy same as helium ≈24.6 eV
formationProcess Big Bang nucleosynthesis NERFINISHED
alpha decay of heavier nuclei
stellar hydrogen fusion
formsSuperfluidPhase true
isAlphaParticle true
isMagicNucleus true
isStable true
magicNeutronNumber 2
magicProtonNumber 2
mass ≈4.002602 u
≈6.6465×10^-27 kg
massNumber 4
meltingPointAt1atm doesNotMelt (solidifies only under pressure)
naturalAbundanceInHelium >0.99
neutronNumber 2
neutronSeparationEnergy high
nuclearSpin 0
nucleonNumber 4
occursIn Sun NERFINISHED
interstellar medium
main-sequence stars
productOf CNO cycle NERFINISHED
proton–proton chain reaction
protonNumber 2
protonSeparationEnergy high
radioactive false
roleInCosmology key probe of Big Bang nucleosynthesis
superfluidTransitionTemperature ≈2.17 K (lambda point)
symbol 4He
totalBindingEnergy ≈28.3 MeV
usedAs carrier gas in some analytical instruments
coolant for superconducting magnets
cryogenic coolant
working fluid in low-temperature physics experiments

Referenced by (1)

Full triples — surface form annotated when it differs from this entity's canonical label.