Title: Ammonium Iodide
CAS Registry Number: 12027-06-4
Molecular Formula: H4IN
Molecular Weight: 144.94
Percent Composition: H 2.78%, I 87.56%, N 9.66%
Line Formula: NH4I
Literature References: Contains about 98% NH4I; about l% ammonium hypophosphite is usually added as a preservative. Prepd from ammonia, iodine and hydrogen peroxide; from ammonia and hydrogen iodide; or from ammonium carbonate and hydrogen iodide: Wulff, Cameron, Z. Phys. Chem. B10, 350 (1930); Schmeisser in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 289. Review: Richards "Ammonium Iodide" in Mellor's vol. VIII, Supplement I, Nitrogen (part 1) 448-458 (1964).
Properties: White, odorless, very hygroscopic, tetragonal crystals or granular powder, sharp saline taste. Becomes yellow to brown on exposure to air and light because of liberation of iodine. When heated it partly decomposes and partly sublimes. d25 2.5142. One gram dissolves in 0.6 ml water, 0.5 ml boiling water, 3.7 ml alc, 1.5 ml glycerol, 2.5 ml methanol. Except in the presence of a stabilizer, such as ammonium hypophosphite, the aq soln will quickly become yellow. The aq soln is nearly neutral to litmus. pH of 0.1M soln about 4.6. Keep tightly closed and protected from light.
Density: d25 2.5142
Use: In photographic chemicals.