Iron(II) bromide
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Iron(II) bromide | |
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Image:Iron(II) bromide.jpg | |
IUPAC name | Iron(II) bromide |
Other names | Ferrous bromide |
Identifiers | |
CAS number | [7789-46-0] |
Properties | |
Molecular formula | FeBr2 |
Molar mass | 215.65 g/mol |
Appearance | yellow-brown solid |
Density | 4.63 g/cm3, solid |
Melting point |
684 °C |
Boiling point |
934 °C |
Solubility in water | soluble |
Solubility in other solvents | THF, methanol, ethanol |
Structure | |
Crystal structure | CdI2 |
Coordination geometry |
octahedral in solid state |
Hazards | |
Main hazards | none |
R-phrases | 20-36/37/38 |
S-phrases | 26-36 |
Related compounds | |
Other anions | Iron(II) chloride |
Other cations | iron(III) bromide |
Related compounds | VBr2 |
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
Iron(II) bromide is the chemical compound FeBr2. This brownish-colored solid is a useful synthetic intermediate; for example it is employed to insert Fe(II) into porphyrins.
Contents |
[edit] Structure
Like most metal halides, FeBr2 adopts a polymeric structure consisting of isolated metal centers cross-linked with halides. It crystallizes with the CdI2 structure, featuring close-packed layers of bromide ions, between which are located Fe(II) ions in octahedral holes.[1] The packing of the halides is slightly different from that for FeCl2, which adopts the CdCl2 motif. FeBr2 also forms hydrates.
[edit] Synthesis
FeBr2 is conveniently synthesized using a methanol solution of concentrated hydrobromic acid. Addition with Fe gives the methanol solvate [Fe(MeOH)6]Br2 together with hydrogen gas. Heating the methanol complex in a vacuum at ca. 160 °C gives pure FeBr2.[2]
[edit] Reactions
FeBr2 reacts with (C2H5)4NBr to give [(C2H5)4N]2FeBr4.[3]
FeBr2 reacts with bromide and bromine to form the intensely colored, mixed-valence species [FeBr3Br9]-.[4]
[edit] References
- ^ Haberecht, J.; Borrmann, H.; Kniep, R. "Refinement of the Crystal Structure of Iron Dibromide, FeBr2 Zeitschrift für Kristallographie - New Crystal Structures (2001), volume 216, page 510.
- ^ G. Winter, "Iron(II) Halides" in "Inorganic Syntheses" 1973, volume 14, pages 101-104.
- ^ N. S. Gill, F.. B. Taylor Inorganic Syntheses 1967, volume 9, page 136-142.
- ^ Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5