Oxygen-16

Last updated
Oxygen-16
Oxygen-162.svg
General
Symbol 16O
Names oxygen-16
Protons (Z)8
Neutrons (N)8
Nuclide data
Natural abundance 99.7621% (SMOW) [1]
Half-life (t1/2)stable
Isotope mass 15.9949146193 [2] Da
Spin 0
Excess energy −4737.00135(16) [3] keV
Isotopes of oxygen
Complete table of nuclides

Oxygen-16 (symbol: 16O or 16
8
O
) is a stable isotope of oxygen, with 8 neutrons and 8 protons in its nucleus, and when not ionized, 8 electrons orbiting the nucleus. It is the most abundant isotope of oxygen, accounting for about 99.76% of all oxygen.

The relative and absolute abundances of oxygen-16 are high because it is a principal product of stellar evolution and because it is a primordial isotope, meaning it can be made by stars that were initially made exclusively of hydrogen. Most oxygen-16 is synthesized at the end of the helium fusion process in stars; the triple-alpha process creates carbon-12, which captures an additional helium-4 to make oxygen-16. It is also created by the neon-burning process.

Oxygen-16 is doubly magic.

Solid samples (organic and inorganic) for oxygen-16 studies are usually stored in silver cups and measured with pyrolysis and mass spectrometry. [4] Researchers need to avoid improper or prolonged storage of the samples for accurate measurements. [4]

Historically, one atomic mass unit was defined as one sixteenth of the mass of an oxygen-16 atom, but has been redefined as one twelfth of the mass of a carbon-12 atom, with the name unified atomic mass unit or dalton .

References

  1. "Reference Sheet for International Measurement Standards" (PDF). International Atomic Energy Agency. December 2006. Archived from the original (PDF) on 2020-07-29.
  2. Wang, Meng; Huang, W.J.; Kondev, F.G.; Audi, G.; Naimi, S. (2021). "The AME 2020 atomic mass evaluation (II). Tables, graphs and references*". Chinese Physics C. 45 (3): 030003. doi:10.1088/1674-1137/abddaf.
  3. Wang, M.; Audi, G.; Kondev, F. G.; Huang, W. J.; Naimi, S.; Xu, X. (2017). "The AME2016 atomic mass evaluation (II). Tables, graphs, and references" (PDF). Chinese Physics C. 41 (3): 030003–8. doi:10.1088/1674-1137/41/3/030003.
  4. 1 2 Tsang, Man-Yin; Yao, Weiqi; Tse, Kevin (2020). Kim, Il-Nam (ed.). "Oxidized silver cups can skew oxygen isotope results of small samples". Experimental Results. 1: e12. doi: 10.1017/exp.2020.15 . ISSN   2516-712X.
Lighter:
oxygen-15
Oxygen-16 is an
isotope of oxygen
Heavier:
oxygen-17
Decay product of:
nitrogen-16
Decay chain
of oxygen-16
Decays to:
stable