Halogens and halides in electric light source products

Halogens include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At), located in Group VIIA of the periodic table. These elements are typical nonmetallic elements and readily combine with typical metals to form salts, hence their collective name: halogens (i.e., salt-forming elements). Halogens directly combined with other elements form compounds known as halides, such as HBr, NaCl, and TII. With the exception of the radioactive element astatine, the other halogens and their halides are commonly used as fillers in electric light sources such as tungsten-halogen incandescent lamps and metal halide lamps.