Ammonium ferric citrate has a range of uses, including: As a food additive, where it has the E number E381, and is used as an acidity regulator. Most notably used in the Scottish beverage Irn-Bru.
Red to brown or green powder
Ferric ammonium citrate is a yellowish brown to red solid with a faint odor of ammonia. It is soluble in water. The primary hazard is the threat to the environment. Immediate steps should be taken to limit its spread to the environment. It is used in medicine, in making blueprints, and as a feed additive.