Beilstein Test for Halogens
Heat the tip of a copper wire in a burner flame until no further coloration of
the flame is noticed. Allow the wire to cool slightly, then dip it into the
unknown (solid or liquid), and again heat it in the flame. A green flash is indicative
of chlorine, blue-green of bromine, and blue of iodine; fluorine is not
detected because copper fluoride is not volatile. The Beilstein test is very sensitive;
halogen-containing impurities may give misleading results. Run the test
on a compound known to contain halogen for comparison to your unknown