Ammonium iodide

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Ammonium iodide
The ammonium cation
The iodide anion
ball-and-stick model of an ammonium cation (left) and an iodide anion (right)
Identifiers
3D model (Jmol)
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
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
Flash point Non-flammable
Related compounds
Other anions
Ammonium fluoride
Ammonium chloride
Ammonium bromide
Other cations
Sodium iodide
Potassium iodide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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]

Preparation[edit]

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 on decomposition of ammoniated nitrogentriiodide (an explosive).

References[edit]

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