Iron(III) bromide

From Wikipedia, the free encyclopedia

Iron(III) bromide
IUPAC name	Iron(III) bromide
Other names	Ferric bromide Iron tribromide
Identifiers
CAS number	[10031-26-2]
Properties
Molecular formula	FeBr₃
Molar mass	295.56 g/mol
Appearance	brown solid
Density	4.50 g cm⁻³
Melting point	200 °C (decomposes)
Hazards
Main hazards	corrosive
R-phrases	36/37/38
S-phrases	26-37/39
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

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

[edit] Structure, synthesis and basic properties

FeBr₃ forms a polymeric structure featuring six-coordinate, octahedral Fe centers.^[1] 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:

FeBr₃ → FeBr₂ + 0.5 Br₂

FeCl₃ is considerably more stable, reflecting the greater oxidizing power of chlorine. And, following conventional trends, FeI₃ is less stable than the tribromide.^[1]