Ammonium Iodide is a derivative of Iodine. Ammonium Iodide is a White Crystalline Powder with a Melting point of 551oC. Ammonium Iodide is freely soluble in water. Ammonium Iodide gradually turns yellow in colour if kept in open for long due to decomposition with the liberation of Iodine. It should be stored in tightly closed containers in a Room Temperature.