Iron can serve as an activator in phosphors, giving a 660 mµ‐peaked red emission. Previous difficulties with the preparation of reproducible samples are overcome with the use of Cl, Br, I, Al, Ga, or In coactivators. The red emission is always accompanied by a 460 mµ blue emission attributed to Cu impurity and/or (more likely) to Zn vacancies. Detailed luminescence characteristics of phosphors under ultraviolet (u.v.) and EL excitation are presented. A model of the Fe center showing the transitions leading to luminescence and killing, which may occur in the same center, is given.