Ammonium bromide

Ammonium bromide
Names
	IUPAC name Ammonium bromide
Identifiers
CAS Number	12124-97-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:85364 ;
ChemSpider	23804 ;
ECHA InfoCard	100.031.973
EC Number	235-183-8;
PubChem CID	25514;
RTECS number	BO9155000liugoiugiu;
UNII	R0JB3224WS ;
CompTox Dashboard (EPA)	DTXSID8035681 ;
	InChI InChI=1S/BrH.H3N/h1H;1H3 Key: SWLVFNYSXGMGBS-UHFFFAOYSA-N ; InChI=1/BrH.H3N/h1H;1H3 Key: SWLVFNYSXGMGBS-UHFFFAOYAP;
	SMILES [Br-].[NH4+];
Properties
Chemical formula	NH4Br
Molar mass	97.94 g/mol
Appearance	white powder, hygroscopic
Density	2.429 g/cm3
Melting point	235 °C (455 °F; 508 K)
Boiling point	452 °C (846 °F; 725 K)
Solubility in water	60.6 g/100 mL (0 °C) ; 78.3 g/100 mL (25 °C) ; 145 g/100 mL (100 °C)
Magnetic susceptibility (χ)	−47.0×10−6 cm3/mol
Refractive index (nD)	1.712
Structure
Crystal structure	Isometric
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
NFPA 704 (fire diamond)	2 0 0
Related compounds
Other anions	Ammonium fluoride; Ammonium chloride; Ammonium iodide
Other cations	Sodium bromide; Potassium bromide
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Ammonium bromide, NH₄Br, is the ammonium salt of hydrobromic acid. The chemical crystallizes in colorless prisms, possessing a saline taste; it sublimes on heating and is easily soluble in water. On exposure to air it gradually assumes a yellow color because of the oxidation of traces of bromide (Br⁻) to bromine (Br₂).

Preparation[edit]

Ammonium bromide can be prepared by the direct action of hydrogen bromide on ammonia.

NH₃ + HBr → NH₄Br

It can also be prepared by the reaction of ammonia with iron(II) bromide or iron(III) bromide, which may be obtained by passing aqueous bromine solution over iron filings.

2 NH₃ + FeBr₂ + 2 H₂O → 2 NH₄Br + Fe(OH)₂

Reactions[edit]

Ammonium bromide is a weak acid with a pK_a of approximately 5 in water. It is an acid salt because the ammonium ion hydrolyzes slightly in water.

Ammonium bromide is a strong electrolyte when put in water:

NH₄Br(s) → NH+4(aq) + Br⁻(aq)

Ammonium bromide decomposes to ammonia and hydrogen bromide when heated at elevated temperatures:

NH₄Br → NH₃ + HBr

Uses[edit]

Ammonium bromide is used for photography in films, plates and papers; in fireproofing of wood; in lithography and process engraving; in corrosion inhibitors; and in pharmaceutical preparations.^[2]

References[edit]

^ ^a ^b Sigma-Aldrich Co., Ammonium bromide.
^ Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8

[sigma-1] Sigma-Aldrich Co., Ammonium bromide.

[2] Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, ISBN 0-07-049439-8

[1]

[2]