ammonium bromide
{{chembox
| Verifiedfields = changed
| Watchedfields = changed
| verifiedrevid = 443525663
| Name = Ammonium bromide
| IUPACName = Ammonium bromide
| ImageFile = Ammonium bromide.svg | ImageSize = 120px
| ImageFile2 = Ammonium-bromide-3D-balls.png
| ImageSize2 = 170px
| ImageName2 = ball-and-stick model of an ammonium cation (left) and a bromide anion (right)
|Section1={{Chembox Identifiers
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = R0JB3224WS
| EC_number = 235-183-8
| InChI = 1/BrH.H3N/h1H;1H3
| SMILES = [Br-].[NH4+]
| InChIKey = SWLVFNYSXGMGBS-UHFFFAOYAP
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/BrH.H3N/h1H;1H3
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = SWLVFNYSXGMGBS-UHFFFAOYSA-N
| CASNo = 12124-97-9
| CASNo_Ref = {{cascite|correct|CAS}}
| RTECS = BO9155000liugoiugiu
| PubChem = 25514
| ChEBI_Ref = {{ebicite|changed|EBI}}
| ChEBI = 85364
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID=23804
}}
|Section2={{Chembox Properties
| Formula = NH4Br
| MolarMass = 97.94 g/mol
| Appearance = white powder, hygroscopic
| MeltingPtC = 235
| BoilingPtC = 452
| Density = 2.429 g/cm3
| Solubility = 60.6 g/100 mL (0 °C)
78.3 g/100 mL (25 °C)
145 g/100 mL (100 °C)
| RefractIndex = 1.712
| MagSus = {{val|−47.0e−6|u=cm3/mol}}
}}
|Section3={{Chembox Structure
| CrystalStruct = Isometric
}}
|Section7={{Chembox Hazards
| GHSPictograms = {{GHS07}}{{Sigma-Aldrich|id=380008|name=Ammonium bromide|access-date=2013-07-20}}
| GHSSignalWord = Warning
| HPhrases = {{H-phrases|315|319|335}}
| PPhrases = {{P-phrases|261|264|271|280|302+352|304+340|305+351+338|312|321|332+313|337+313|362|403+233|405|501}}
| NFPA-H = 2
| NFPA-F = 0
| NFPA-R = 0
}}
|Section8={{Chembox Related
| OtherAnions = Ammonium fluoride
Ammonium chloride
Ammonium iodide
| OtherCations = Sodium bromide
Potassium bromide
}}
}}
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 bromide (Br−) to bromine (Br2).
Preparation
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
Ammonium bromide is a weak acid with a pKa of approximately 9 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) → {{chem2|NH4+}}(aq) + Br−(aq)
Ammonium bromide decomposes to ammonia and hydrogen bromide when heated at elevated temperatures:
: NH4Br → NH3 + HBr
Uses
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.Pradyot Patnaik. Handbook of Inorganic Chemicals. McGraw-Hill, 2002, {{ISBN|0-07-049439-8}}
References
{{reflist}}
{{Ammonium salts}}
{{bromides}}