36ClCl

36ClCl refers to a diatomic chlorine molecule in which both chlorine atoms are the radioactive isotope chlorine-36. In isotope labeling, such a species is sometimes described as 36Cl2 or 36Cl-36Cl, representing an isotopically enriched form of Cl2 used as a radiotracer. Natural chlorine primarily consists of 35Cl and 37Cl, with 36Cl present only in trace amounts due to cosmogenic production and long half-life.

Properties and decay: 36Cl decays by beta minus decay to 36Ar with a half-life of about 301,000 years. Because of its long half-life, 36Cl behaves as a long-lived tracer in environmental and chemical studies. The decay emits beta radiation, and any accompanying gamma emissions are weak; detection is typically achieved through radiometric or accelerator-based techniques rather than gamma spectroscopy alone.

Production and preparation: 36Cl can be produced by neutron capture on stable 35Cl (35Cl(n, gamma)36Cl) in a nuclear reactor or by spallation reactions in accelerators. After production, the isotope can be incorporated into chlorine-containing compounds and, in principle, assembled into Cl2 to form labeled molecules such as 36ClCl. In practice, labeling workflows consider isotope exchange and chemical equilibration to achieve the desired isotopologue distribution.

Applications: 36ClCl is used as a radiotracer to study chlorine transport and reaction kinetics in groundwater, soils, and atmospheric chemistry. It supports dating and tracing applications when combined with sensitive detection methods, such as accelerator mass spectrometry (AMS), which can measure 36Cl at very low abundances.

Safety: handling requires radiological controls, appropriate shielding, and regulatory waste management due to its long-lived radioactivity. See also: chlorine isotopes, radiotracers, chlorine dating, accelerator mass spectrometry.