Ammonium iodide

Ammonium iodide is the inorganic compound with the formula NH₄I. A white solid. It is an ionic compound, although impure samples appear yellow. This salt consists of ammonium cation and an iodide anion.^[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. Ammonium iodide in aqueous solutions are observed as acidic and display elevated vapor pressures at high temperatures.^[2]

Ammonium iodide

The ammonium cation The iodide anion
ball-and-stick model of an ammonium cation (left) and an iodide anion (right)
Identifiers
CAS Number	12027-06-4 Y
3D model (JSmol)	Interactive image
ChemSpider	23785 Y
ECHA InfoCard	100.031.548
PubChem CID	25487
UNII	OZ8F027LDH Y
CompTox Dashboard (EPA)	DTXSID60894063
InChI InChI=1S/HI.H3N/h1H;1H3 Y Key: UKFWSNCTAHXBQN-UHFFFAOYSA-N Y InChI=1/HI.H3N/h1H;1H3 Key: UKFWSNCTAHXBQN-UHFFFAOYAU
SMILES [I-].[NH4+]
Properties
Chemical formula	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)
Solubility in water	155 g/100 mL (0 °C) 172 g/100 mL (20 °C) 250 g/100 mL (100 °C)
Magnetic susceptibility (χ)	−66.0×10−6 cm3/mol
Hazards
NFPA 704 (fire diamond)	2 0 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 treating ammonia with hydroiodic acid:

NH₃ + HI → NH₄I

Uses

Ammonium iodide is used as dietary supplement to treat iodine deficiency.^[3]

Properties and reactions

Vinyl sulfones have been prepared using ammonium iodide.^[4]

In green chemistry, ammonium iodide and an oxidant (e.g., H₂O₂) cleanly iodinate ketones and aromatic compounds.^[5]