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This 1975 phase diagram of chlorine is generally incomplete, reaching at most 250 kbar (25 GPa) and thus lacking many high-pressure metallic phases. Credit: David A. Young.{{free media}}

This phase diagram was taken from "Phase Diagrams of the Elements", David A. Young, UCRL-51902 "Prepared for the U.S. Energy Research & Development Administration under contract No. W-7405-Eng-48".


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Chlorine emission spectrum is from 400 nm - 700 nm. Credit: McZusatz.{{free media}}


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Chlorine gas is contained in an ampoule. Credit: W. Oelen.{{free media}}

Chlorine is a "toxic, green gaseous chemical element".[1]


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Liquid chlorine is contained in a flask for analysis. Credit: Workingclass91.{{free media}}
Liquid chlorine is under pressure in an "acrylic glass" (i.e., Plexiglas, Lucite) cube. Credit: Alchemist-hp.{{free media}}

On the right is liquid chlorine (Cl2) contained in a flask for analysis. Liquid chlorine is yellow in color.

Image on the left is an ampoule containing liquid chlorine. It has been liquefied under pressure at >7.4 bar, sealed in the quartz vial (ampoule), further sealed in an "acrylic glass" (i.e., Plexiglas, Lucite) cube, cube edge length: 5 cm.

Cosmic rays

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"Chlorine-36 is produced in rocks at the surface of the earth by cosmic-ray spallation, mainly of K and Ca, and by activation of 35Cl by cosmic-ray neutrons (PHILLIPS et al., 1986; FABRYKA-MARTIN, 1988). Cosmogenic 36Cl significantly above subsurface concentrations is produced only to depths of a few meters below the earth’s surface (FABRYKA-MARTIN, 1988; LAL, 1987), and its buildup has been shown to be a regular function of time (PHILLIPS et al., 1986). Zreda et al. (1990, 1991) have determined 36Cl production rates (normalized to sea level and 90” N latitude) of 4,160 ± 310 atoms 36Cl (mol K)-1 yr-1 and 3,050 ± 210 atoms 36Cl (mol Ca)-1 yr-1, and a thermal neutron capture rate of (3.07 ± 0.24)*105 neutrons (kg rock)-1 yr-1. Meteor Crater is an excellent subject for cosmogenic nuclide accumulation dating because we can identify and sample one geological unit (the Kaibab Formation) that was virtually completely shielded from cosmic rays by 10 m of Moenkopi Sandstone prior to the impact (RODDY, 1978). Boulders of Kaibab Formation were nearly instantaneously exposed to cosmic radiation when they were ejected from the crater by the impact. The date of the impact can be determined by measuring the amount of cosmogenic 36Cl that has accumulated, provided that the boulder surfaces are not strongly eroded. Erosion rates in the range of millimeters per thousand years will have little effect on cosmogenic 36Cl dates, but loss of slabs of decimeter or greater thickness would reduce the apparent age."[2]

36Cl "is created by high-energy cosmic-ray neutron reactions on potassium and calcium and low energy neutron reactions on stable chlorine."[3]

"Chlorine-36 buildup dating has successfully been applied to glacial moraines in the eastern Sierra Nevada (California) and to lava flows and meteorite impact craters in the western United States."[3]

Chlorine-36 nuclides are also measured to date surface rocks. This isotope may be produced by cosmic ray spallation of calcium or potassium.[4]


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See also

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  1. chlorine. San Francisco, California: Wikimedia Foundation, Inc. 28 August 2013. Retrieved 5 October 2013. 
  2. Fred M. Phillips; Marek G. Zreda; Stewart S. Smith; David Elmore; Peter W. Kubik; Ronald I. Dorn; David J. Roddy (September 1991). "Age and geomorphic history of Meteor Crater, Arizona, from cosmogenic 36C1 and 14C in rock varnish". Geochimica et Cosmochimica Acta 55 (9): 2695-8. Retrieved 2014-01-23. 
  3. 3.0 3.1 F.M. Phillips; D.Q. Bowen; E. Elmore (1994). "Surface exposure dating of glacial features in Great Britain using cosmogenic chlorine-36: preliminary results". Mineralogical Magazine 58A: 722-3. Retrieved 2014-09-21. 
  4. Stone, J; Allan, G; Fifield, L; Cresswell, R (1996). "Cosmogenic chlorine-36 from calcium spallation". Geochimica et Cosmochimica Acta 60 (4): 679. doi:10.1016/0016-7037(95)00429-7.