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Isotopes of Chlorine

List, data and properties of all known isotopes of Chlorine as well as radioactive decay products and intermediate products.

 

Chlorine isotopes

24 isotopes and some nuclear isomers of the chemical element chlorine are known. The individual nuclides differ in the number of neutrons in the atomic nucleus; What all Cl isotopes have in common is the number of protons and - in the uncharged, neutral state - of electrons: 17.

 

Naturally Occurring Chlorine Isotopes

Natural chlorine deposits are composed of the stable isotopes chlorine-35 and chlorine-37 in a 3:1 ratio and traces (7 x 10-13 atoms to 1 stable chlorine atom) of the radioisotope chlorine-36 together; the latter is mainly produced by the effects of cosmic radiation on 40Ar and 36Ar and radioactively decays to 36Ar and with a half-life of 308000 years 36p. 36Cl is used in geological dating.

Atomic Mass maQuantityHalf-lifeSpin
Chlorine
Isotopic mixture
35,45 u100 %
Isotope 35Cl34,9688527(3) u75,8 %stable3/2+
Isotope 36Cl35,96830682(4) utraces3.013(15) × 105 a2+
Isotope 37Cl36,9659026(4) u24,2 %stable3/2+

 

The atomic mass varies between 35.446 and 35.457 u, corresponding to the fluctuations in the isotopic composition of natural chlorine.

All other chlorine isotopes are radioactive and decay with half-lives of less than 1 hour.

 

Isotope Table: Chlorine

 

Atomic Properties

Isotope
Nuclide
ZANNameAtomic Mass
[Nuclear Mass]
{Mass Excess}
Spin I
(h/2π)
μParent
123456789
28Cl172811Chlorine-2828.02954(64) u
[28.0202143 u]
{27.51633 MeV}
1+
29Cl172912Chlorine-2929.01413(20) u
[29.0048043 u]
{13.16201 MeV}
(1/2+)
30Cl173013Chlorine-3030.00477(21) u
[29.9954443 u]
{4.44323 MeV}
(3+)
31Cl173114Chlorine-3130.992448(4) u
[30.9831223 u]
{-7.03464 MeV}
3/2+31Ar
32Cl173215Chlorine-3231.9856846(6) u
[31.9763589 u]
{-13.33471 MeV}
1+1.115(6)32Ar
33Cl173316Chlorine-3332.9774520(4) u
[32.9681263 u]
{-21.00333 MeV}
3/2++ 0.7547(3)33Ar
35Ca
34Cl173417Chlorine-3433.97376249(5) u
[33.9644368 u]
{-24.44008 MeV}
0+34Ar
35K
34mCl173417Chlorine-34m33.97376249(5) u
[33.9644368 u]
{-24.44008 MeV}
3+
35Cl173518Chlorine-3534.9688527(3) u
[34.959527 u]
{-29.01352 MeV}
3/2++0.82170(2)35Ar
35S
36K
36Cl173619Chlorine-3635.96830682(4) u
[35.9589811 u]
{-29.52201 MeV}
2++1.2849(3)
37Cl173720Chlorine-3736.9659026(4) u
[36.9565769 u]
{-31.76152 MeV}
3/2++0.68400(1)37Ar
37S
38Cl173821Chlorine-3837.96801042(11) u
[37.9586847 u]
{-29.7981 MeV}
2-2.05(2)38S
38mCl173821Chlorine-38m37.96801042(11) u
[37.9586847 u]
{-29.7981 MeV}
5-
39Cl173922Chlorine-3938.9680082(19) u
[38.9586825 u]
{-29.80017 MeV}
3/2+39S
40Cl174023Chlorine-4039.97042(3) u
[39.9610943 u]
{-27.55359 MeV}
2-40S
41Cl174124Chlorine-4140.97068(7) u
[40.9613543 u]
{-27.3114 MeV}
(1/2+)41S
42Cl174225Chlorine-4241.97334(6) u
[41.9640143 u]
{-24.83363 MeV}
(2-)42S
43S
43Cl174326Chlorine-4342.97406(7) u
[42.9647343 u]
{-24.16295 MeV}
(1/2+)43S
44S
44Cl174427Chlorine-4443.97812(15) u
[43.9687943 u]
{-20.38109 MeV}
(2-)(-) 0.5498(4)44S
45Cl174528Chlorine-4544.98039(15) u
[44.9710643 u]
{-18.2666 MeV}
(1/2+)
46Cl174629Chlorine-4645.98512(22) u
[45.9757943 u]
{-13.86063 MeV}
(2-)
47Cl174730Chlorine-4746.98950(43) u
[46.9801743 u]
{-9.78069 MeV}
3/2+
48Cl174831Chlorine-4847.99541(54) u
[47.9860843 u]
{-4.27556 MeV}
49Cl174932Chlorine-4949.00101(64) u
[48.9916843 u]
{0.94081 MeV}
3/2+
50Cl175033Chlorine-5050.00831(64) u
[49.9989843 u]
{7.74072 MeV}
51Cl175134Chlorine-5151.01534(75) u
[51.0060143 u]
{14.28912 MeV}
(3/2+)

 

Radioactive Decay Properties

IsotopeRadioactive DecayAEExtern
Half-lifeDecay ModeProbabilityEnergy
1101112131415
Cl-28p → 27SAL
Cl-2920 nsp → 28SAL
Cl-3030 nsp → 29SAL
Cl-31190(1) msβ+31S
β+, p → 30P
97.6 %
2.4(2) %
11.9769 MeV
5.844 MeV
AL
Cl-32298(1) msEC/β+32S
ε, p → 31P
EC, α → 28Si
99.92 %
0.26 %
0.054 %
12.6804 MeV
3.822 MeV
5.738 MeV
AL
Cl-332.511(4) sEC/β+33S100 %5.58259 MeVAL
Cl-341.5266(4) sEC/β+34S100 %5.49163 MeVAL
Cl-34m31.99(3) minEC/β+34S
Iso → 34Cl
55.4(6) %
44.6(6) %
5.638 MeV
0.146 MeV
146.36(3) keVAL
Cl-35stableAL
Cl-363.013(15) × 105 aEC/β+36S
β-36Ar
1.9(1) %
98.1(1) %
1.14214 MeV
0.70955 MeV
AL
Cl-37stableAL
Cl-3837.230(14) minβ-38Ar100 %4.91662 MeVAL
Cl-38m715(3) msIso → 38Cl100 %0.671 MeV671.365(8) keVAL
Cl-3956.2(6) minβ-39Ar100 %3.44197 MeVAL
Cl-401.35(2) minβ-40Ar100 %7.48208 MeVAL
Cl-4138.4(8) sβ-41Ar100 %5.76031 MeVAL
Cl-426.8(3) sβ-42Ar100 %9.50968 MeVAL
Cl-433.13(9) sβ-43Ar100 %7.60166 MeVAL
Cl-440.56(11) sβ-44Ar
β-, n → 43Ar
> 92 %
< 8 %
12.06806 MeV
3.33331 MeV
AL
Cl-45413(25) msβ-45Ar
β-, n → 44Ar
76(4) %
24(4) %
11.41103 MeV
6.2422 MeV
AL
Cl-46232(2) msβ-46Ar
β-, n → 45Ar
40(9) %
60(9) %
15.9192 MeV
7.8891 MeV
AL
Cl-47101(6) msβ-47Ar
β-, n → 46Ar
97 %
< 3 %
15.59(40) MeV
11.92(40) MeV
AL
Cl-48200 nsβ-48Ar?18.00(59) MeVAL
Cl-49170 nsβ-49Ar?18.13(72) MeVAL
Cl-50620 nsβ- ? 50Ar
β-, n,2n,3n ?


AL
Cl-51200 nsβ- ? 51ArAL

 

Notes (related to the columns):

1 - nuclide, isotope symbol.
2 - Z = number of protons (atomic number).
3 - Mass number A.
4 - N = number of neutrons.
5 - Identification of the Chlorine isotope.
6 - Relative atomic mass of the Chlorine isotope (isotopic mass including electrons) and the mass of the atomic nucleus in square brackets (nuclear mass, nuclide mass without electrons), each related to 12C = 12.00000 [2]. In addition, the mass excess is given in MeV.
7 - Nuclear spin I, unit: h/2π.
8 - Nuclear magnetic moment μmag.
9 - Source nuclides: Possible, assumed or actual source nuclides (mother nuclides, parent nuclides). If applicable, the corresponding decay modes can be found in the data for the respective starting nuclide.
10 - Decay: Half-live of the Chlorine isotope (a = years; ; d = days; h = hours; min = minutes; s = seconds).
11 - Decay: type of decay into the respective daughter nuclides with n = neutron emission; p = proton emission; α = alpha decay; β- = beta minus decay with electron emission; EC = electron capture; β+ = positron emission; ε = β+ and/or EC; Iso = isomeric transition; CD = cluster decay; SF = spontaneous decay.
12 - Decay percentage in percent (%).
13 - Decay energy; Particle energy related to decay type.
14 - AE = Excitation energy for metastable nuclei.
15 - Other information and notes: AL = Adopted Levels (link to external data [1]).

Miscellaneous:

()- Numbers in brackets: uncertainty to represent the spread of the reported value.
~ - Theoretical values or systematic trends.
  - unlisted-: Nuclides that have already been mentioned in the literature but for some reason can no longer be found in the current nuclide tables because their discovery e.g. has not confirmed.

 

NMR active Chlorine nuclides

Nuclide
quantity 1)
spin
Nuclear magnetic
moment
μ/μN
Gyromagnetic
ratio
107 rad T-1 s-1
Quadrupole
moment
Q fm-2
Resonant
frequency
v0 bei 1 T
Relative
sensitivity
H0 = const.
v0 = const. 2)
35Cl
75,8 %
3/2+
+0,82170(2)2,624- 8,1124,17650,00472
0,4905
37Cl
24,2 %
3/2+
+0,68400(1)2,1842- 6,3933,47650,00272
0,4083

1) Quantity Percentage of natural occurrence.

2) Related to 1H = 1,000.

 

Radiation Protection

According to the Radiation Protection Ordinance (StrlSchV 2018, Germany), the following values (columns 1 to 7) apply to the handling of Chlorine radionuclides:

NuclideLimit ValueHASS limitSCDaughter NuclidesHalf-life
Cl-36106 Bq1 Bq/g20 TBq100 Bq/cm2300000 a
Cl-38105 Bq10 Bq/g0,05 TBq1 Bq/cm237.2 min
Cl-39105 Bq10 Bq/g55.6 min

(HASS = High-Activity Sealed Radioactive Sources; SC = surface contamination)

 

Literature Sources and References

Properties of the Chlorine nucleides

[1] - NuDat: National Nuclear Data Center, Brookhaven National Laboratory, based on ENSDF and the Nuclear Wallet Cards.

[2] - G. Audi et. al.: The NUBASE evaluation of nuclear and decay properties. Nuclear Physics, (2003), DOI 10.1016/j.nuclphysa.2003.11.001.

[3] - Live Chart of Nuclides. Nuclear structure and decay data.

Chlorine: NMR properties - 35Cl-NMR, 37Cl-NMR

[4] - N. J. Stone: Table of nuclear magnetic dipole and electric quadrupole moments. Atomic Data and Nuclear Data Tables, (2005), DOI 10.1016/j.adt.2005.04.001.

[5] - Pekka Pyykkö: Year-2008 nuclear quadrupole moments. Molecular Physics, (2008), DOI 10.1080/00268970802018367.

[6] - Pekka Pyykkö: Year-2017 nuclear quadrupole moments. Molecular Physics, (2018), DOI 10.1080/00268976.2018.1426131.

[7] - N. J. Stone: Table of recommended nuclear magnetic dipole moments. IAEA, (2019).

More sources:

[8] - Isotopic abundances, atomic weights and isotopic masses: see respective keyword.

 


Category: Isotopes

Last update: 05.07.2020



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