How to find isotopes of chlorine

1. ^ mCl – Excited nuclear isomer.
2. ^ ( ) – Uncertainty (1σ) is given in concise form in parentheses after the corresponding last digits.
3. ^ # – Atomic mass marked #: value and uncertainty derived not from purely experimental data, but at least partly from trends from the Mass Surface (TMS).
4. ^ a b # – Values marked # are not purely derived from experimental data, but at least partly from trends of neighboring nuclides (TNN).
5. ^ Modes of decay:

   IT:	Isomeric transition
   n:	Neutron emission
   p:	Proton emission

6. ^ Bold symbol as daughter – Daughter product is stable.
7. ^ ( ) spin value – Indicates spin with weak assignment arguments.
8. ^ Used in radiodating water
9. ^ Cosmogenic nuclide

Main article: Chlorine-36

Trace amounts of radioactive 36Cl exist in the environment, in a ratio of about 7×10−13 to 1 with stable isotopes. 36Cl is produced in the atmosphere by spallation of 36Ar by interactions with cosmic ray protons. In the subsurface environment, 36Cl is generated primarily as a result of neutron capture by 35Cl or muon capture by 40Ca. 36Cl decays to either 36S (1.9%) or to 36Ar (98.1%), with a combined half-life of 308,000 years. The half-life of this hydrophilic nonreactive isotope makes it suitable for geologic dating in the range of 60,000 to 1 million years. Additionally, large amounts of 36Cl were produced by neutron irradiation of seawater during atmospheric detonations of nuclear weapons between 1952 and 1958. The residence time of 36Cl in the atmosphere is about 1 week. Thus, as an event marker of 1950s water in soil and ground water, 36Cl is also useful for dating waters less than 50 years before the present. 36Cl has seen use in other areas of the geological sciences, forecasts, and elements. In chloride-based molten salt reactors the production of 36
Cl by neutron capture is an inevitable consequence of using natural isotope mixtures of chlorine (i.e. Those containing 35
Cl). This produces a long lived radioactive product which has to be stored or disposed off. Isotope separation to produce pure 37
Cl can vastly reduce 36
Cl production, but a small amount might still be produced by (n,2n) reactions involving fast neutrons.

Main article: Chlorine-37

Stable chlorine-37 makes up about 24.23% of the naturally occurring chlorine on earth. Variation occurs as chloride mineral deposits have a slightly elevated chlorine-37 balance over the average found in sea water and halite deposits.[citation needed]

1. ^ "Standard Atomic Weights: Chlorine". CIAAW. 2009.
2. ^ Meija, Juris; et al. (2016). "Atomic weights of the elements 2013 (IUPAC Technical Report)". Pure and Applied Chemistry. 88 (3): 265–91. doi:10.1515/pac-2015-0305.
3. ^ Half-life, decay mode, nuclear spin, and isotopic composition is sourced in:
   Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001.
4. ^ 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): 030003-1–030003-442. doi:10.1088/1674-1137/41/3/030003.
5. ^ a b c Mukha, I.; et al. (2018). "Deep excursion beyond the proton dripline. I. Argon and chlorine isotope chains". Physical Review C. 98 (6): 064308–1—064308–13. arXiv:1803.10951. doi:10.1103/PhysRevC.98.064308.
6. ^ Neufcourt, L.; Cao, Y.; Nazarewicz, W.; Olsen, E.; Viens, F. (2019). "Neutron drip line in the Ca region from Bayesian model averaging". Physical Review Letters. 122: 062502–1—062502–6. arXiv:1901.07632. doi:10.1103/PhysRevLett.122.062502.

• Chlorine isotopes data from The Berkeley Laboratory Isotopes Project's