Iron(III) bromide

Iron(III) bromide is the chemical compound with the formula FeBr₃. Also known as ferric bromide, this red-brown odorless compound is used as a Lewis acid catalyst in the halogenation of aromatic compounds. It dissolves in water to give acidic solutions.

Iron(III) bromide

Names
IUPAC name Iron(III) bromide
Other names Ferric bromide Iron tribromide tribromoiron
Identifiers
CAS Number	10031-26-2 Y
3D model (JSmol)	Interactive image
ChemSpider	23830 Y
ECHA InfoCard	100.030.069
EC Number	233-089-1
PubChem CID	25554
UNII	9RDO128EH7 Y
CompTox Dashboard (EPA)	DTXSID40894107
InChI InChI=1S/3BrH.Fe/h3*1H;/q;;;+3/p-3 Y Key: FEONEKOZSGPOFN-UHFFFAOYSA-K N InChI=1/3BrH.Fe/h3*1H;/q;;;+3/p-3 Key: FEONEKOZSGPOFN-DFZHHIFOAP
SMILES [Fe](Br)(Br)Br
Properties
Chemical formula	FeBr3
Molar mass	295.56 g mol−1
Appearance	brown solid
Odor	odorless
Density	4.50 g cm−3
Melting point	200 °C (392 °F; 473 K) (decomposes)
Structure
Crystal structure	Trigonal, hR24
Space group	R-3, No. 148
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	corrosive
GHS labelling:[1]
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
NFPA 704 (fire diamond)	3 0 0
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

Structure, synthesis and basic properties

FeBr₃ forms a polymeric structure featuring six-coordinate, octahedral Fe centers.^[2] Although inexpensively available commercially, FeBr₃ can be prepared by treatment of iron metal with bromine:

2 Fe + 3 Br₂ → 2 FeBr₃

Above 200 °C, FeBr₃ decomposes to ferrous bromide:

2FeBr₃ → 2FeBr₂ + Br₂

Iron(III) chloride is considerably more stable, reflecting the greater oxidizing power of chlorine. FeI₃ is not stable, as iron(III) will oxidize iodide ions.

Uses

Ferric bromide is occasionally used as an oxidant in organic chemistry, e.g. for the conversion of alcohols to ketones. It is used as a Lewis acidic catalyst for bromination of aromatic compounds. For the latter applications, it is often generated in situ.^[3]

See also

• Iron(II) bromide, the lower bromide of iron

References

1. "C&L Inventory". echa.europa.eu.
2. Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
3. Drapeau, Martin Pichette; Lafantaisie, Mathieu; Ollevier, Thierry (2013). "Iron(III) bromide". E-EROS Encyclopedia of Reagents for Organic Synthesis. doi:10.1002/047084289X.rn01568. ISBN 978-0471936237.