Chlorine-37

Source: Wikipedia, the free encyclopedia.
Chlorine-37, 37Cl
General
Symbol37Cl
Nameschlorine-37, 37Cl, Cl-37
Protons (Z)17
Neutrons (N)20
Nuclide data
Natural abundance24.23%
Isotope mass36.965903 Da
Isotopes of chlorine
Complete table of nuclides

Chlorine-37 (37
Cl
), is one of the

neutrons for a total of 37 nucleons. Chlorine-37 accounts for 24.23% of natural chlorine, chlorine-35 accounting for 75.77%, giving chlorine atoms in bulk an apparent atomic weight of 35.453(2) g/mol.[1]

Remarkably, solar neutrinos were discovered by an experiment using a radiochemical method based on chlorine-37 transmutation.[2]

Neutrino detection

Main article: Homestake experiment

One of the historically important radiochemical methods of solar neutrino detection is based on inverse electron capture triggered by the absorption of an electron neutrino.[3] Chlorine-37 transmutes into argon-37 via the reaction[4]

37
Cl
 +
ν
e → 37
Ar
 +
e−
.

Argon-37 then de-excites itself via electron capture (half-life = 35 d) into chlorine-37 via the reaction

37
Ar
 +
e−
 → 37
Cl
 +
ν
e.

These last reactions involve

Auger electrons of specific energies.[3][5] The detection of these electrons confirms that a neutrino event took place. Detection methods involve several hundred thousand liters of carbon tetrachloride (CCl4) or tetrachloroethylene (C2Cl4) stored in underground tanks.[2][3][6]

Occurrence

The representative terrestrial abundance of chlorine-37 is 24.22(4)% of chlorine atoms,

Standard Reference Material (975a) also exists. SMOC is known to be around 24.219% chlorine-37 and to have an atomic weight of around 35.4525.[8]

There is a known variation in the isotopic abundance of chlorine-37. This heavier isotope tends to be more prevalent in chloride minerals than in aqueous solutions such as sea water, although the isotopic composition of

parts per thousand.[8]

See also

References

  1. doi:10.1351/pac200678112051
  2. ^ a b J.N. Bahcall (1969). "Neutrinos from the Sun".
    doi:10.1038/scientificamerican0769-28
    .
  3. ^ a b c Sutton, Christine (1992). Spaceship Neutrino.
    OCLC 25246163
    . chlorine-37 neutrino.
  4. ^ F.H. Shu (1982). The Physical Universe: An Introduction to Astronomy. University Science Books. p. 122.
    ISBN 978-0-935702-05-7
    . chlorine 37 neutrino.
  5. ^ A.H. Snell, F. Pleasonton (1955). "Spectrometry of the Neutrino Recoils of Argon-37".
    doi:10.1103/PhysRev.100.1396
    .
  6. ISBN 978-981-238-244-3
    .
  7. doi:10.1351/pac199870010217
  8. ^
    doi:10.1351/pac200375060683
Retrieved from "https://en.wikipedia.org/w/index.php?title=Chlorine-37&oldid=1221714455"