Isotopes of chlorine Isotopes of chlorine Chlorine (Cl) has 25 isotopes with mass numbers ranging from Cl to Cl and 2 isomers (Cl and Cl). There are two principal stable isotopes, Cl (75.78%) and Cl (24.22%), giving chlorine a standard atomic weight of 35.45. The longest-lived radioactive isotope is Cl, 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 Cl and Cl, with half-lives less than 20 and 30 nanoseconds, respectively—the half-life of Cl is unknown. Bromine is the only other halogen with more than one stable isotope. Trace
Bromine salt saturated with chlorine and extracted the bromine with diethyl ether. After evaporation of the ether a brown liquid remained. With this liquid as a sample of his work he applied for a position in the laboratory of Leopold Gmelin in Heidelberg. The publication of the results was delayed and Balard published his results first. Balard found bromine chemicals in the ash of seaweed from the salt marshes of Montpellier. The seaweed was used to produce iodine, but also contained bromine. Balard distilled the bromine from a solution of seaweed ash saturated with chlorine. The properties of the resulting substance