Editing Halogen (section)

===== Metal halides =====
{{main|Metal halides}}
All the halogens are known to react with sodium to form [[sodium fluoride]], [[sodium chloride]], [[sodium bromide]], [[sodium iodide]], and sodium astatide. Heated sodium's reaction with halogens produces bright-orange flames. Sodium's reaction with chlorine is in the form of:

: {{math|2Na + Cl<sub>2</sub> → 2NaCl}}<ref name = "assorted"/>

Iron reacts with fluorine, chlorine, and bromine to form iron(III) halides. These reactions are in the form of:

: {{math|2Fe + 3X<sub>2</sub> → 2FeX<sub>3</sub>}}<ref name = "assorted"/>

However, when iron reacts with iodine, it forms only [[iron(II) iodide]].

: {{math|Fe + I<sub>2</sub> → FeI<sub>2</sub>}}

Iron wool can react rapidly with fluorine to form the white compound [[iron(III) fluoride]] even in cold temperatures. When chlorine comes into contact with a heated iron, they react to form the black [[iron(III) chloride]]. However, if the reaction conditions are moist, this reaction will instead result in a reddish-brown product. Iron can also react with bromine to form [[iron(III) bromide]]. This compound is reddish-brown in dry conditions. Iron's reaction with bromine is less reactive than its reaction with fluorine or chlorine. A hot iron can also react with iodine, but it forms iron(II) iodide. This compound may be gray, but the reaction is always contaminated with excess iodine, so it is not known for sure. Iron's reaction with iodine is less vigorous than its reaction with the lighter halogens.<ref name = "assorted"/>