Isotopes of chlorine
Encyclopedia
Chlorine
(Cl) has 24 isotopes with mass numbers ranging from 28Cl to 51Cl and 2 isomers (34mCl and 38mCl). There are two principal stable isotope
s, 35Cl (75.78%) and 37Cl (24.22%), found in the relative proportions of 37.89:12.11, not 3:1, respectively, giving chlorine a standard atomic mass of 35.453, not 35.5. The longest-lived radioactive isotope is 36Cl which has a half-life of 301,000 years. All other isotopes have half-lives under 1 hour, many less than one second. The shortest-lived are 29Cl and 30Cl, wiith half-lives less than 20 and 30 nanoseconds, respectively—the half-life of 28Cl is unknown.
Standard atomic mass: 35.453(2) u
of 36Ar
by interactions with cosmic ray
proton
s. In the subsurface environment, 36Cl is generated primarily as a result of neutron capture
by 35Cl or muon capture
by 40Ca
. 36Cl decays to 36S
(1.9%) and 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 irradiation of seawater
during atmospheric detonations of nuclear weapon
s 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.
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
(Cl) has 24 isotopes with mass numbers ranging from 28Cl to 51Cl and 2 isomers (34mCl and 38mCl). There are two principal stable isotope
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
s, 35Cl (75.78%) and 37Cl (24.22%), found in the relative proportions of 37.89:12.11, not 3:1, respectively, giving chlorine a standard atomic mass of 35.453, not 35.5. The longest-lived radioactive isotope is 36Cl which has a half-life of 301,000 years. All other isotopes have half-lives under 1 hour, many less than one second. The shortest-lived are 29Cl and 30Cl, wiith half-lives less than 20 and 30 nanoseconds, respectively—the half-life of 28Cl is unknown.
Standard atomic mass: 35.453(2) u
Chlorine-36 (36Cl)
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 spallationSpallation
In general, spallation is a process in which fragments of material are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection or vaporization of material from a target during impact by a projectile...
of 36Ar
Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...
by interactions with cosmic ray
Cosmic ray
Cosmic rays are energetic charged subatomic particles, originating from outer space. They may produce secondary particles that penetrate the Earth's atmosphere and surface. The term ray is historical as cosmic rays were thought to be electromagnetic radiation...
proton
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s. In the subsurface environment, 36Cl is generated primarily as a result of neutron capture
Neutron capture
Neutron capture is a kind of nuclear reaction in which an atomic nucleus collides with one or more neutrons and they merge to form a heavier nucleus. Since neutrons have no electric charge they can enter a nucleus more easily than positively charged protons, which are repelled...
by 35Cl or muon capture
Muon capture
Muon capture is the capture of a negative muon by a proton, usually resulting in production of a neutron and a neutrino, and sometimes a gamma photon....
by 40Ca
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
. 36Cl decays to 36S
Sulfur
Sulfur or sulphur is the chemical element with atomic number 16. In the periodic table it is represented by the symbol S. It is an abundant, multivalent non-metal. Under normal conditions, sulfur atoms form cyclic octatomic molecules with chemical formula S8. Elemental sulfur is a bright yellow...
(1.9%) and to 36Ar
Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...
(98.1%), with a combined half-life
Half-life
Half-life, abbreviated t½, is the period of time it takes for the amount of a substance undergoing decay to decrease by half. The name was originally used to describe a characteristic of unstable atoms , but it may apply to any quantity which follows a set-rate decay.The original term, dating to...
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 irradiation of seawater
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
during atmospheric detonations of nuclear weapon
Nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission or a combination of fission and fusion. Both reactions release vast quantities of energy from relatively small amounts of matter. The first fission bomb test released the same amount...
s 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
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
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.
Table
| nuclide symbol |
Z(p Proton The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number.... ) |
N(n Neutron The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of... ) |
isotopic mass (u) |
half-life | decay mode(s)Abbreviations: IT: Isomeric transition Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... |
daughter isotope(s)Bold for stable isotopes |
nuclear spin |
representative isotopic composition (mole fraction) |
range of natural variation (mole fraction) |
|---|---|---|---|---|---|---|---|---|---|
| excitation energy | |||||||||
| 28Cl | 17 | 11 | 28.02851(54)# | p Proton emission Proton emission is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state of very... |
27S | (1+)# | |||
| 29Cl | 17 | 12 | 29.01411(21)# | <20 ns | p | 28S | (3/2+)# | ||
| 30Cl | 17 | 13 | 30.00477(21)# | <30 ns | p | 29S | (3+)# | ||
| 31Cl | 17 | 14 | 30.99241(5) | 150(25) ms | β+ Beta decay In nuclear physics, beta decay is a type of radioactive decay in which a beta particle is emitted from an atom. There are two types of beta decay: beta minus and beta plus. In the case of beta decay that produces an electron emission, it is referred to as beta minus , while in the case of a... (99.3%) |
31S | 3/2+ | ||
| β+, p (.7%) | 30P | ||||||||
| 32Cl | 17 | 15 | 31.985690(7) | 298(1) ms | β+ (99.92%) | 32S | 1+ | ||
| β+, α Alpha decay Alpha decay is a type of radioactive decay in which an atomic nucleus emits an alpha particle and thereby transforms into an atom with a mass number 4 less and atomic number 2 less... (.054%) |
28Al | ||||||||
| β+, p (.026%) | 31P | ||||||||
| 33Cl | 17 | 16 | 32.9774519(5) | 2.511(3) s | β+ | 33S | 3/2+ | ||
| 34Cl | 17 | 17 | 33.97376282(19) | 1.5264(14) s | β+ | 34S | 0+ | ||
| 34mCl | 146.36(3) keV | 32.00(4) min | β+ (55.4%) | 34S | 3+ | ||||
| IT Isomeric transition An isomeric transition is a radioactive decay process that involves emission of a gamma ray from an atom where the nucleus is in an excited metastable state, referred to in its excited state, as a nuclear isomer.... (44.6%) |
34Cl | ||||||||
| 35Cl | 17 | 18 | 34.96885268(4) | Stable | 3/2+ | 0.7576(10) | 0.75644-0.75923 | ||
| 36Cl Chlorine-36 Chlorine-36 is an isotope of chlorine. Chlorine has two stable isotopes and one radioactive environmental isotope: the cosmogenic isotope 36Cl. The ratio of 36Cl to stable 37Cl in the environment is ~700 × 10−15. Its half-life is 301,000 ± 4,000 years. The long half-life of 36Cl makes it... Used in radiodating water |
17 | 19 | 35.96830698(8) | 3.01(2)×105 y | β- (98.1%) | 36Ar | 2+ | TraceCosmogenic nuclide Cosmogenic nuclide See also Environmental radioactivity#NaturalCosmogenic nuclides are rare isotopes created when a high-energy cosmic ray interacts with the nucleus of an in situ solar system atom, causing cosmic ray spallation... |
approx. 7*10-13 |
| ε (1.9%) | 36S | ||||||||
| 37Cl Chlorine-37 Chlorine-37, or ', is one of the stable isotopes of chlorine, the other being chlorine-35 . Its nucleus contains 17 protons and 20 neutrons for a total of 37 nucleons... |
17 | 20 | 36.96590259(5) | Stable | 3/2+ | 0.2424(10) | 0.24077-0.24356 | ||
| 38Cl | 17 | 21 | 37.96801043(10) | 37.24(5) min | β- | 38Ar | 2- | ||
| 38mCl | 671.361(8) keV | 715(3) ms | IT | 38Cl | 5- | ||||
| 39Cl | 17 | 22 | 38.9680082(19) | 55.6(2) min | β- | 39Ar | 3/2+ | ||
| 40Cl | 17 | 23 | 39.97042(3) | 1.35(2) min | β- | 40Ar | 2- | ||
| 41Cl | 17 | 24 | 40.97068(7) | 38.4(8) s | β- | 41Ar | (1/2+,3/2+) | ||
| 42Cl | 17 | 25 | 41.97325(15) | 6.8(3) s | β- | 42Ar | |||
| 43Cl | 17 | 26 | 42.97405(17) | 3.07(7) s | β- (>99.9%) | 43Ar | 3/2+# | ||
| β-, n Neutron emission Neutron emission is a type of radioactive decay of atoms containing excess neutrons, in which a neutron is simply ejected from the nucleus. Two examples of isotopes which emit neutrons are helium-5 and beryllium-13... (<.1%) |
42Ar | ||||||||
| 44Cl | 17 | 27 | 43.97828(12) | 0.56(11) s | β- (92%) | 44Ar | |||
| β-, n (8%) | 43Ar | ||||||||
| 45Cl | 17 | 28 | 44.98029(13) | 400(40) ms | β- (76%) | 45Ar | 3/2+# | ||
| β-, n (24%) | 44Ar | ||||||||
| 46Cl | 17 | 29 | 45.98421(77) | 232(2) ms | β-, n (60%) | 45Ar | |||
| β- (40%) | 46Ar | ||||||||
| 47Cl | 17 | 30 | 46.98871(64)# | 101(6) ms | β- (97%) | 47Ar | 3/2+# | ||
| β-, n (3%) | 46Ar | ||||||||
| 48Cl | 17 | 31 | 47.99495(75)# | 100# ms [>200 ns] | β- | 48Ar | |||
| 49Cl | 17 | 32 | 49.00032(86)# | 50# ms [>200 ns] | β- | 49Ar | 3/2+# | ||
| 50Cl | 17 | 33 | 50.00784(97)# | 20# ms | β- | 50Ar | |||
| 51Cl | 17 | 34 | 51.01449(107)# | 2# ms [>200 ns] | β- | 51Ar | 3/2+# | ||