copper(I) bromide
{{redirect|CuBr|the "Centro Universitario de Bienestar Rural"|FUNDAEC}}
{{chembox
| verifiedrevid = 411104199
| Name = Copper(I) bromide
| ImageFile = Copper(I) bromide.jpg
| ImageName = Sample of copper(I) bromide
| ImageFile1 = Sphalerite-unit-cell-depth-fade-3D-balls.png
| ImageName1 = Structure of CuBr
| OtherNames = Cuprous bromide
|Section1={{Chembox Identifiers
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| ChemSpiderID = 22995
| InChI = 1/BrH.Cu/h1H;/q;+1/p-1
| SMILES = Br[Cu]
| InChIKey = NKNDPYCGAZPOFS-REWHXWOFAY
| StdInChI_Ref = {{stdinchicite|correct|chemspider}}
| StdInChI = 1S/BrH.Cu/h1H;/q;+1/p-1
| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}
| StdInChIKey = NKNDPYCGAZPOFS-UHFFFAOYSA-M
| CASNo = 7787-70-4
| CASNo_Ref = {{cascite|correct|CAS}}
| UNII_Ref = {{fdacite|correct|FDA}}
| UNII = R8V209A5G0
| PubChem = 24593
}}
|Section2={{Chembox Properties
| Formula = CuBr
| MolarMass = 143.45 g/mol
| Appearance = white powder (see text)
| Density = 4.71 g/cm3, solid
| MeltingPtC = 492
| BoilingPtC = 1345
| Solubility = insoluble;
slightly soluble in cold water
| SolubleOther = soluble in HCl, HBr, ammonium hydroxide, acetonitrile
negligible in acetone, sulfuric acid
| SolubilityProduct = {{val|6.27e-9}}{{cite book |first=John |last=Rumble |title=CRC Handbook of Chemistry and Physics |date=June 18, 2018 |publisher=CRC Press |isbn=978-1138561632 |pages=5–188|edition=99th |language=English}}
| RefractIndex = 2.116
| Dipole = 1.46 D
| MagSus = {{val|-49.0e-6|u=cm3/mol}}
}}
|Section3={{Chembox Hazards
| ExternalSDS =
| FlashPt = Non-flammable
| PEL = TWA 1 mg/m3 (as Cu){{PGCH|0150}}
| IDLH = TWA 100 mg/m3 (as Cu)
}}
|Section8={{Chembox Related
| OtherAnions = Copper(I) chloride
Copper(I) iodide
| OtherCations = Silver(I) bromide
Copper(II) bromide
Mercury(I) bromide
}}
}}
Copper(I) bromide is the chemical compound with the formula CuBr. This white diamagnetic solid adopts a polymeric structure akin to that for zinc sulfide. The compound is widely used in the synthesis of organic compounds and as a lasing medium in copper bromide lasers.
Preparation, basic properties, structure
The compound is white, although samples are often colored due to the presence of copper(II) impurities.Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. {{ISBN|0-12-352651-5}}. The copper(I) ion also oxidizes easily in air. It is commonly prepared by the reduction of cupric salts with sulfite in the presence of bromide.This report gives a procedure for generating CuBr: {{OrgSynth | first = Jonathan L. |last=Hartwell | title = o-Chlorobromobenzene | collvol = 3 | collvolpages = 185 | year = 1955 | prep = cv3p0185}} For example, the reduction of copper(II) bromide with sulfite yields copper(I) bromide and hydrogen bromide:
:2 CuBr2 + H2O + {{chem|SO|3|2-}} → 2 CuBr + {{chem|SO|4|2-}} + 2 HBr
CuBr is insoluble in most solvents due to its polymeric structure, which features four-coordinated, tetrahedral Cu centers interconnected by bromide ligands (ZnS structure). Upon treatment with Lewis bases, CuBr converts to molecular adducts. For example, with dimethyl sulfide, the colorless complex is formed:{{OrgSynth |last1=Jarowicki |first1=K. |last2=Kocienski |first2=P. J. |last3=Qun |first3=L. |title=1,2-Metallate Rearrangement: (Z)-4-(2-Propenyl)-3-Octen-1-ol |volume=79 |pages=11 |collvol=10 |collvolpages=662 |date=2004 |prep=v79p0011}}
:CuBr + S(CH3)2 → CuBr(S(CH3)2)
In this coordination complex, the copper is two-coordinate, with a linear geometry. Other soft ligands afford related complexes. For example, triphenylphosphine gives CuBr(P(C6H5)3), although this species has a more complex structure.
Thermal excitation of copper(I) bromide vapour yields a blue-violet emission which is of greater saturation than known copper(I) chloride emission.{{cite journal|first=E.-C. |last=Koch |title=Spectral Investigation and Color Properties of Copper(I) Halides CuX (X=F, Cl, Br, I) in Pyrotechnic Combustion Flames |journal=Propellants Explos. Pyrotech. |date=2015 |volume=40 |issue=6 |pages=798–802 |doi=10.1002/prep.201500231 |url=http://onlinelibrary.wiley.com/wol1/doi/10.1002/prep.201500231/abstract}} Copper(I) bromide is hence an advantageous emitter in pyrotechnic flames.
Applications in organic chemistry
In the Sandmeyer reaction, CuBr is employed to convert diazonium salts into the corresponding aryl bromides:
:{{chem|ArN|2|+}} + CuBr → ArBr + N2 + Cu+
The aforementioned complex CuBr(S(CH3)2) is widely used to generate organocopper reagents. Related CuBr complexes are catalysts for atom transfer radical polymerization and copper-catalyzed cross-dehydrogenative couplings (CDC).
See also
References
{{reflist}}
External links
{{Commons category|Copper(I) bromide}}
- [http://www.webelements.com/webelements/compounds/text/Cu/Br1Cu1-7787704.html Web Elements]
{{Copper compounds}}
{{bromides}}