Ammonium iodide

Structural formula
General
Surname	Ammonium iodide
other names	Iodammonium
Molecular formula	NH 4 I.
Brief description	white, odorless solid
External identifiers / databases
CAS number 12027-06-4 EC number 234-717-7 ECHA InfoCard 100,031,548 PubChem 25487 Wikidata Q413953
properties
Molar mass	144.94 g mol −1
Physical state	firmly
density	2.51 g cm −3 (20 ° C)
Melting point	551 ° C ( sublimed )
solubility	very light in water (1770 g l −1 at 25 ° C)
safety instructions
GHS labeling of hazardous substances Caution H and P phrases H: 315-319 P: 261-280-305 + 351 + 338-304 + 340-405-501
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Ammonium iodide is the ammonium salt of hydrogen iodide .

properties

Ammonium iodide forms white , cubic crystals that are easily soluble in water and ethanol . It is easily decomposable and turns yellow to brown in air as a result of the oxidation of the iodide ion to iodine I ₂ . The compound occurs in three crystal structures, the low-temperature form having a tetragonal crystal structure with the space group P 4 / nmm (space group no. 129) .

synthesis

Ammonium iodide can be produced by the reaction of iodine or hydrogen iodide with ammonia or ammonium carbonate :

${\displaystyle \mathrm {3\ I_{2}+8\ NH_{3}\longrightarrow 6\ NH_{4}I+N_{2}} }$

${\displaystyle \mathrm {NH_{3}+HI\longrightarrow NH_{4}I} }$

${\displaystyle \mathrm {(NH_{4})_{2}CO_{3}\cdot H_{2}O+2\ HI\longrightarrow 2\ NH_{4}I+2\ H_{2}O+CO_{2}} }$

However, caution should be exercised in the reaction between iodine I ₂ and ammonia water, since iodine nitrogen is formed very easily .

In the laboratory, ammonium iodide solution is similarly obtained from 10% ammonia water , iodine and hydrogen peroxide :

${\displaystyle \mathrm {I_{2}+2\ NH_{3}+H_{2}O_{2}\longrightarrow 2\ NH_{4}I+O_{2}} }$

use

Ammonium iodide is used in the phototechnical industry and in medicine.

Individual evidence

1. ↑ ^{a b c d} Entry on ammonium iodide in the GESTIS substance database of the IFA , accessed on January 9, 2019(JavaScript required) .
2. ↑ ^{a b} Data sheet Ammonium iodide, 98 +% from AlfaAesar, accessed on February 1, 2019 ( PDF )(JavaScript required) .
3. ^ Ammonium iodide - article in Meyers Konversationslexikon, Verlag des Bibliographisches Institut, Leipzig and Vienna, fourth edition, 1885-1892
4. ^ High Pressure Phase Transformations: A Handbook . CRC Press, 1992, ISBN 978-2-88124-759-0 , pp. 445 ( books.google.de ).
5. ↑ G. Brauer (Ed.), Handbook of Preparative Inorganic Chemistry 2nd ed., Vol. 1, Academic Press 1963, pp. 289-90.