Halide refers to the chemical-combining form of any of the HALOGEN elements: fluorine, chlorine, bromine, and iodine. A halide may be any compound that contains a halogen atom, such as sodium chloride (table salt) or stannous fluoride (tooth decay preventative), or a mineral such as fluorspar, that contains a halogen element. Chloroform is an example of an organic halide or, more specifically, an alkyl halide.