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
Compounds of fluorine state is −1. It differs from this value in elemental fluorine, where the atoms are bonded to each other and thus at oxidation state 0, and a few polyatomic ions: the very unstable anions and with intermediate oxidation states exist at very low temperatures, decomposing at around 40 K. Also, the cation and a few related species have been predicted to be stable. Fluorine forms compounds with all elements except neon and helium. In particular, it forms binary compounds, named fluorides, with all said elements except argon. All of the elements up to einsteinium, element 99, have been checked except