Chlorine Chlorine Chlorine is a chemical element with symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine is a yellow-green gas at room temperature. It is an extremely reactive element and a strong oxidising agent: among the elements, it has the highest electron affinity and the third-highest electronegativity, behind only oxygen and fluorine. The most common compound of chlorine, sodium chloride (common salt), has been known since ancient times. Around 1630, chlorine gas was first synthesised in a chemical reaction,
Bromine pentafluoride Bromine pentafluoride Bromine pentafluoride, BrF, is an interhalogen compound and a fluoride of bromine. It is a strong fluorination reagent. BrF finds use in oxygen isotope analysis. Laser ablation of solid silicates in the presence of bromine pentafluoride releases O for subsequent analysis. It has also been tested as an oxidizer in liquid rocket propellants and is used as a fluorinating agent in the processing of uranium. Bromine pentafluoride was first prepared in 1931 by the direct reaction of bromine with fluorine. This reaction is suitable for the preparation of large quantities, and is carried out at temperatures over with