Iron(II) bromide: Difference between revisions

| Verifiedfields = changed

| verifiedrevid = 432513551

| Name = Iron(II) bromide

| ImageFile1 =FeBr2(aq)4.svg

| ImageFile2 = Cadmium-iodide-3D-layers.png

| ImageName = Iron(II) bromide

| IUPACName = Iron(II) bromide

| OtherNames = Ferrous bromide

| SystematicName =

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| CASNo_Ref = {{cascite|correct|??}}

| CASNo1 = 20049-61-0

| CASNo1_Comment= tetrahydrate

| CASNo2 = 7789-46-0

| CASNo2_Comment= anhydrous

| UNII_Ref = {{fdacite|correct|FDA}}

| UNII = EA3X054RBZ

| PubChem = 425646

| RTECS =

| Formula = FeBr₂

| MolarMass = 215.65 g mol⁻¹

| Appearance = yellow-brown solid

| Density = 4.63 g cm⁻³, solid

| Solubility = 117 g / 100 ml

| Solvent = other solvents

| SolubleOther = [[THF]], [[methanol]], [[ethanol]]

| MeltingPtC = 684

| MeltingPt_notes = (anhydrous) <br> 27 °C (Hexahydrate)

| BoilingPtC = 934

| MagSus = +13,600·10⁻⁶ cm³/mol

| Coordination = octahedral

| CrystalStruct = [[Rhombohedral]], [[Pearson symbol|hP3]], SpaceGroup = P-3m1, No. 164

| Dipole =

| Section4 =

| Section5 =

| Section6 =

| ExternalSDS =

| MainHazards = none

| FlashPt =

| OtherAnions = [[Iron(II) fluoride]]<br>[[Iron(II) chloride]]<br>[[Iron(II) iodide]]

| OtherCations = [[Manganese(II) bromide]]<br>[[Cobalt(II) bromide]]

| OtherFunction_label = compounds

| OtherFunction = [[Vanadium(II) bromide]]<br>[[Iron(III) bromide]]

[[File:Бромид железа.jpg|alt=Iron(II) bromide|thumb|Iron(II) bromide anhydrous]]

'''Iron(II) bromide''' refers to [[inorganic compound]]s with the chemical formula FeBr₂(H₂O)_x. The anhydrous compound (x = 0) is a yellow or brownish-colored paramagnetic solid. The [[water of crystallization|tetrahydrate]] is also known, all being pale colored solids. They are common precursor to other iron compounds.

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.<ref>{{cite journal|doi=10.1524/ncrs.2001.216.14.544|title=Refinement of the crystal structure of iron dibromide, FeBr2|journal=Zeitschrift für Kristallographie - New Crystal Structures|volume=216|issue=1–4|year=2001|last1=Haberecht|first1=J.|last2=Borrmann|first2=Η.|last3=Kniep|first3=R.|doi-access=free}}</ref> The packing of the halides is slightly different from that for FeCl₂, which adopts the CdCl₂ motif. The tetrahydrates FeX₂(H₂O)₄ (X = Cl, Br) have similar structures, with octahedral metal centers and mutually trans halides.<ref>{{cite journal |doi=10.1016/S0020-1693(00)80756-2| title=X-ray Structural Studies of FeBr₂·4H₂O, CoBr₂·4H₂O, NiCl₂·4H₂O and CuBr₂·4H₂O. Cis/Trans Selectivity in Transition Metal(II) Dihalide Tetrahydrate | year=1992 | last1=Waizumi | first1=Kenji | last2=Masuda | first2=Hideki | last3=Ohtaki | first3=Hitoshi | journal=Inorganica Chimica Acta | volume=192 | issue=2 | pages=173–181 }}</ref>

==Synthesis and reactions==

FeBr₂ is synthesized using a [[methanol]] solution of concentrated [[hydrobromic acid]] and iron powder. It adds the methanol solvate [Fe(MeOH)₆]Br₂ together with hydrogen gas. Heating the methanol complex in a vacuum gives pure FeBr₂.<ref>{{cite book|doi=10.1002/9780470132456.ch20|chapter=Iron(II) Halides|series=Inorganic Syntheses|pages=99–104|year=1973|volume=14| last1=Winter|first1=G.|title=Inorganic Syntheses|isbn=9780470132456}}</ref>

FeBr₂ reacts with two equivalents of [[tetraethylammonium bromide]] to give [(C₂H₅)₄N]₂FeBr₄.<ref>N. S. Gill, F.. B. Taylor Inorganic Syntheses 1967, volume 9, page 136-142. {{doi| 10.1002/9780470132401.ch37}}</ref> FeBr₂ reacts with bromide and bromine to form the intensely colored, mixed-valence species [FeBr₃Br₉]⁻.<ref>Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}</ref>

==Magnetism==

FeBr₂ possesses a strong [[metamagnetism]] at 4.2&nbsp;[[Kelvin|K]] and has long been studied as a prototypical metamagnetic compound.<ref>{{cite journal |last1=Wilkinson |first1=M. K. |last2=Cable |first2=J. W. |last3=Wollan |first3=E. O. |last4=Koehler |first4=W. C. |title=Neutron Diffraction Investigations of the Magnetic Ordering in FeBr₂, CoBr₂, FeCl₂, and CoCl₂ |journal=Physical Review |date=15 January 1959 |volume=113 |issue=2 |pages=497–507 |doi=10.1103/PhysRev.113.497|bibcode=1959PhRv..113..497W }}</ref><ref>{{cite journal |last1=Jacobs |first1=I. S. |last2=Lawrence |first2=P. E. |title=Metamagnetic Phase Transitions and Hysteresis in FeCl₂ |journal=Physical Review |date=10 December 1967 |volume=164 |issue=2 |pages=866–878 |doi=10.1103/PhysRev.164.866|bibcode=1967PhRv..164..866J }}</ref>

{{bromine compounds}}

[[Category:Iron(II) compounds]]