Ammonium iodide

Ammonium iodide is the chemical compound NH4I. It is used in photographic chemicals and some medications.[1] It can be prepared by the action of hydroiodic acid on ammonia. It is easily soluble in water, from which it crystallizes in cubes. It is also soluble in ethanol. It gradually turns yellow on standing in moist air, owing to decomposition with liberation of iodine.[1]

Ammonium iodide
The ammonium cation
The iodide anion
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.548
UNII
Properties
NH4I
Molar mass 144.94 g/mol
Appearance White crystalline powder
Density 2.51 g/cm3
Melting point 551 °C (1,024 °F; 824 K) (sublimes)
Boiling point 235 °C (455 °F; 508 K) (in vacuum)
155 g/100 mL (0 °C)
172 g/100 mL (20 °C)
250 g/100 mL (100 °C)
-66.0·10−6 cm3/mol
Hazards
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g. chloroformReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no code
0
2
0
Flash point Non-flammable
Related compounds
Other anions
 Ammonium fluoride
Ammonium chloride
Ammonium bromide
Other cations
 Sodium iodide
Potassium iodide
Phosphonium iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N verify (what is YN ?)
Infobox references

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 triiodoamine (an explosive).

References
  1. Holleman, A. F.; Wiberg, E. Inorganic Chemistry Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
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