Chlorine electron affinity, enthalpy of dissociation of the X molecule (X = Cl, Br, I), ionic radius, and X–X bond length. (Fluorine is anomalous due to its small size.) All four stable halogens experience intermolecular van der Waals forces of attraction, and their strength increases together with the number of electrons among all homonuclear diatomic halogen molecules. Thus, the melting and boiling points of chlorine are intermediate between those of fluorine and bromine: chlorine melts at −101.0 °C and boils at −34.0 °C. As a result of the increasing molecular weight of the halogens down the group, the density and heats
Fluorine perchlorate in a rare oxidation state of 0, due to the electronegativity of oxygen, which is higher than that of chlorine but lower than that of fluorine. FClO has a very dangerous and unpredictable series of reactions associated with it, as a covalent perchlorate (chlorine in the +7 oxidation state) and a compound featuring a very sensitive O-F single bond. Small amounts of reducing agent, such as organic compounds, can trigger explosive detonation. Products of these decomposition reactions could include oxygen halides, interhalogen compounds, and other hazardous substances. Accidental synthesis is possible if precursors are carelessly mixed. Like similar covalent fluorides