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| Names | |
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| Other names
Cuprous bromide
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| Identifiers | |
3D model (JSmol)
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| ChemSpider |
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| ECHA InfoCard | 100.029.210 |
PubChem CID
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| UNII | |
CompTox Dashboard (EPA)
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| Properties | |
| CuBr | |
| Molar mass | 143.45 g/mol |
| Appearance | white powder (see text) |
| Density | 4.71 g/cm3, solid |
| Melting point | 492 °C (918 °F; 765 K) |
| Boiling point | 1,345 °C (2,453 °F; 1,618 K) |
| insoluble; slightly soluble in cold water | |
Solubility product (Ksp)
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6.27×10−91 |
| Solubility | soluble in HCl, HBr, ammonium hydroxide, acetonitrile negligible in acetone, sulfuric acid |
| −49.0×10−6 cm3/mol | |
Refractive index (nD)
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2.116 |
| 1.46 D | |
| Hazards | |
| GHS labelling:3 | |
  
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| Danger | |
| H302+H312, H315, H318, H319, H335, H410 | |
| P261, P264, P264+P265, P270, P271, P273, P280, P301+P317, P302+P352, P304+P340, P305+P351+P338, P305+P354+P338, P317, P319, P321, P330, P332+P317, P337+P317, P362+P364, P391, P403+P233, P405, P501 | |
| Flash point | Non-flammable |
| NIOSH (US health exposure limits): | |
PEL (Permissible)
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TWA 1 mg/m3 (as Cu)2 |
REL (Recommended)
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TWA 1 mg/m3 (as Cu)2 |
IDLH (Immediate danger)
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TWA 100 mg/m3 (as Cu)2 |
| Related compounds | |
Other anions
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Copper(I) chloride Copper(I) iodide |
Other cations
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Silver(I) bromide Copper(II) bromide Mercury(I) bromide |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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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.
Properties
The compound is white, although samples are often colored due to the presence of copper(II) impurities.4 The copper(I) ion also oxidizes easily in air. CuBr is insoluble in most solvents due to its polymeric structure, which features four-coordinated, tetrahedral Cu centers interconnected by bromide ligands (ZnS structure).
Thermal excitation of copper(I) bromide vapour yields a blue-violet emission which is of greater saturation than known copper(I) chloride emission.5 Copper(I) bromide is hence an advantageous emitter in pyrotechnic flames.
Preparation
It is commonly prepared by the reduction of cupric salts with sulfite in the presence of bromide.6 For example, the reduction of copper(II) bromide with sulfite yields copper(I) bromide and hydrogen bromide:
- 2 CuBr2 + H2O + SO2−
3 → 2 CuBr + SO2−
4 + 2 HBr
Applications in organic chemistry
In the Sandmeyer reaction, CuBr is employed to convert diazonium salts into the corresponding aryl bromides:6
- ArN+
2 + CuBr → ArBr + N2 + Cu+
The aforementioned complex CuBr(S(CH3)2) is widely used to generate organocopper reagents.7 Related CuBr complexes are catalysts for atom transfer radical polymerization and copper-catalyzed cross dehydrogenative couplings (CDCs).
Reactions
Upon treatment with Lewis bases, CuBr converts to molecular adducts. For example, with dimethyl sulfide, the colorless complex is formed:7
- 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.
References
References
- Rumble, John (June 18, 2018). CRC Handbook of Chemistry and Physics (99th ed.). CRC Press. pp. 5–188. ISBN 978-1138561632.
- NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH).
- PubChem. "copper(I) bromide". pubchem.ncbi.nlm.nih.gov. Retrieved 2026-02-17.
- Holleman, A. F.; Wiberg, E. "Inorganic Chemistry" Academic Press: San Diego, 2001. ISBN 0-12-352651-5.
- Koch, E.-C. (2015). "Spectral Investigation and Color Properties of Copper(I) Halides CuX (X=F, Cl, Br, I) in Pyrotechnic Combustion Flames". Propellants Explos. Pyrotech. 40 (6): 798–802. doi:10.1002/prep.201500231.
- This report gives a procedure for generating CuBr: Hartwell, Jonathan L. (1955). "o-Chlorobromobenzene". Organic Syntheses; Collected Volumes, vol. 3, p. 185.
- Jarowicki, K.; Kocienski, P. J.; Qun, L. "1,2-Metallate Rearrangement: (Z)-4-(2-Propenyl)-3-Octen-1-ol". Organic Syntheses. 79: 11; Collected Volumes, vol. 10, p. 662.