Dimer (chemistry) dimerise to give the dimer "A-A". An example is a diaminocarbene, which dimerise to give a tetraaminoethylene: Carbenes are highly reactive and readily form bonds. Dicyclopentadiene is an asymmetrical dimer of two cyclopentadiene molecules that have reacted in a Diels-Alder reaction to give the product. Upon heating, it "cracks" (undergoes a retro-Diels-Alder reaction) to give identical monomers: Many nonmetallic elements occur as dimers: hydrogen, nitrogen, oxygen, the halogens, i.e. fluorine, chlorine, bromine and iodine. Noble gases can form dimers linked by van der Waals bonds, for example dihelium or diargon. Mercury occurs as a mercury(I) cation (Hg), formally a dimeric
Bromine trifluoride Bromine trifluoride Bromine trifluoride is an interhalogen compound with the formula BrF. It is a straw-coloured liquid with a pungent odor. It is soluble in sulfuric acid but reacts violently with water and organic compounds. It is a powerful fluorinating agent and an ionizing inorganic solvent. It is used to produce uranium hexafluoride (UF) in the processing and reprocessing of nuclear fuel. Bromine trifluoride was first described by Paul Lebeau in 1906, who obtained the material by the reaction of bromine with fluorine at 20 °C: The disproportionation of bromine monofluoride also gives bromine trifluoride: Like ClF and IF, the