Chlorine grew until the part failed. The fracture surface shows iron and calcium salts that were deposited in the leaking joint from the water supply before failure. The element iron can combine with chlorine at high temperatures in a strong exothermic reaction, creating a "chlorine-iron fire". Chlorine-iron fires are a risk in chemical process plants, where much of the pipework that carries chlorine gas is made of steel. 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
Bromine disproportionating quickly and irreversibly into bromine, bromine trifluoride, and bromine pentafluoride. It thus cannot be obtained pure. It may be synthesised by the direct reaction of the elements, or by the comproportionation of bromine and bromine trifluoride at high temperatures. Bromine monochloride (BrCl), a red-brown gas, quite readily dissociates reversibly into bromine and chlorine at room temperature and thus also cannot be obtained pure, though it can be made by the reversible direct reaction of its elements in the gas phase or in carbon tetrachloride. Bromine monofluoride in ethanol readily leads to the monobromination of the aromatic compounds PhX ("para"-bromination