Ammonium iodide is the

chemical compound A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...

NH₄I. It is used in

photographic Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed i ...

chemical A chemical substance is a form of matter having constant chemical composition and characteristic properties. Some references add that chemical substance cannot be separated into its constituent elements by physical separation methods, i.e., wi ...

s and some

medication A medication (also called medicament, medicine, pharmaceutical drug, medicinal drug or simply drug) is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy (pharmacotherapy) is an important part of the medical field and re ...

s.Holleman, A. F.; Wiberg, E. ''Inorganic Chemistry'' Academic Press: San Diego, 2001. . It can be prepared by the action of

hydroiodic acid Hydroiodic acid (or hydriodic acid) is an aqueous solution of hydrogen iodide (HI). It is a strong acid, one that is ionized completely in an aqueous solution. It is colorless. Concentrated solutions are usually 48% to 57% HI. Reactions Hyd ...

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous was ...

. It is easily soluble in

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

, from which it crystallizes in cubes. It is also soluble in

ethanol Ethanol (abbr. EtOH; also called ethyl alcohol, grain alcohol, drinking alcohol, or simply alcohol) is an organic compound. It is an Alcohol (chemistry), alcohol with the chemical formula . Its formula can be also written as or (an ethyl ...

. It gradually turns yellow on standing in moist air, owing to decomposition with liberation of

iodine Iodine is a chemical element with the symbol I and atomic number 53. The heaviest of the stable halogens, it exists as a semi-lustrous, non-metallic solid at standard conditions that melts to form a deep violet liquid at , and boils to a vi ...

Preparation

Ammonium iodide can be made in lab by reacting ammonia or ammonium hydroxide with hydroiodic acid or hydrogen iodide gas: : NH₃ + HI → NH₄I : NH₄OH + HI → NH₄I + H₂O It is also formed by the decomposition of ammoniated

nitrogen triiodide Nitrogen triiodide is an inorganic compound with the formula N I3. It is an extremely sensitive contact explosive: small quantities explode with a loud, sharp snap when touched even lightly, releasing a purple cloud of iodine vapor; it can even b ...

(an explosive).

References

Iodides Nonmetal halides Ammonium compounds {{inorganic-compound-stub