Copper(II) bromide

Copper (II) bromide

Anhydrous

Tetrahydrate

Names
Other names

Cupric bromide
Copper dibromide

Identifiers

CAS Number

* 7789-45-9 Y

3D model (JSmol)

* Interactive image

ChemSpider |

* 8395631 Y

EC Number |

* 232-167-2

PubChem CID

* 24611

UNII |

* 1KC430K0ZN Y

InChI

* InChI=1S/2BrH.Cu/h2*1H;/q;;+2/p-2 Y

Key: QTMDXZNDVAMKGV-UHFFFAOYSA-L Y

* InChI=1/2BrH.Cu/h2*1H;/q;;+2/p-2

Key: QTMDXZNDVAMKGV-NUQVWONBAD

SMILES

* [Cu+2].[Br-].[Br-]

Properties

Chemical formula

| CuBr2
Molar mass | 223.37 g/mol
Appearance  | grayish black crystals
deliquescent
Density | 4.710 g/cm3, solid
Melting point |  498 °C (928 °F; 771 K)
Boiling point |  900 °C (1,650 °F; 1,170 K)

Solubility in water

| 55.7 g/100 mL (20 °C)
Solubility | Soluble in alcohol, acetone, ammonia, insoluble in benzene, ether, ethyl ether, sulfuric acid

Magnetic susceptibility (χ)

| +685.5·10−6 cm3/mol
Structure

Crystal structure

| monoclinic
Hazards
NFPA 704 (fire diamond)  |

NIOSH (US health exposure limits):

PEL (Permissible)

| TWA 1 mg/m3 (as Cu)[1]

REL (Recommended)

| TWA 1 mg/m3 (as Cu)[1]

IDLH (Immediate danger)

| TWA 100 mg/m3 (as Cu)[1]
Related compounds

Other anions

| Copper(II) fluoride
Copper(II) chloride

Other cations

| Copper(I) bromide
Nickel(II) bromide
Zinc bromide
Cadmium bromide
Mercury(II) bromide

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Y verify (what is YN ?)
Infobox references

Copper(II) bromide (CuBr2) is a chemical compound that forms an unstable tetrahydrate CuBr2·4H2O. It is used in photographic processing as an intensifier and as a brominating agent in organic synthesis.[2]

It is also used in the copper vapor laser, a class of laser where the medium is copper bromide vapour formed in-situ from hydrogen bromide reacting with the copper discharge tube.[3] Producing yellow or green light, it is used in dermatological applications.

## Contents

* 1 Synthesis
* 2 Purification
* 3 Molecular and crystal structure
* 4 Reactions
* 5 Usage
* 6 Safety
* 7 Natural occurrence
* 8 See also
* 9 References

## Synthesis

Copper(II) bromide can be obtained by combining copper oxide and hydrobromic acid:[4]

CuO + 2HBr → CuBr2 \+ H2O.

The tetrahydrate can be produced by recrystallization of solutions of copper(II) bromide at 0 °C. If heated above 18 °C, it releases water to produce the anhydrous form.[5]

## Purification

Copper(II) bromide is purified by crystallization twice from water, filtration to remove any CuBr and concentration under vacuum. This product is dehydrated using phosphorus pentoxide.[6]

## Molecular and crystal structure

Crystal structure of copper(II) bromide

In the solid state CuBr2 has a polymeric structure, with CuBr4 planar units connected on opposite sides to form chains. The crystal structure is monoclinic, space group C2/m, with lattice constants a = 714 pm, b = 346 pm, c = 718 pm, e ß = 121° 15'.[7] CuBr2 monomeric units are present in the gas phase at high temperature.[8]

The tetrahydrate, structurally formulated as [CuBr2(H2O)2]·2H2O, has a monoclinic crystal structure and consists of distorted square planartrans-[CuBr2(H2O)2] centres as well as two molecules of water.[5]

## Reactions

Copper(II) bromide in chloroform-ethyl acetate reacts with ketones resulting in the formation of alpha-bromo ketones. The resulting product can be directly used for the preparation of derivatives. This heterogeneous method is reported to be the most selective and direct method of formation of α-bromo ketones.[9]

Dibromination of NPGs, n-pentenyl glycosides, using CuBr2/LiBr reagent combination was performed in order for an NPG to serve as a glycosyl acceptor during halonium-promoted couplings. Such reaction gives high yield of the dibromides from alkenyl sugars that are resistant to a direct reaction with molecular bromine.[10]

## Usage

Copper(II) bromide lasers produce pulsed yellow and green light and have been studied as a possible treatment for cutaneous lesions.[11] Experiments have also shown copper bromide treatment to be beneficial for skin rejuvenation.[12] It has been widely used in photography as its solution was used as the bleaching step for intensifying collodion and gelatin negatives.[13] Copper(II)bromide has also been proposed as a possible material in humidity indicator cards.[14]

## Safety

Copper(II) bromide is harmful if swallowed. It affects the central nervous system, brain, eyes, liver, and kidneys. It causes irritation to skin, eyes, and respiratory tract.

## Natural occurrence

Pure copper(II) bromide is as yet (2020) unknown among minerals. However, barlowite, Cu4BrF(OH)6, contains both copper and bromide.[15][16]

## See also

Copper(I) bromide

## References

1. ↑ 1.0 1.1 1.2 NIOSH Pocket Guide to Chemical Hazards. "#0150". National Institute for Occupational Safety and Health (NIOSH). https://www.cdc.gov/niosh/npg/npgd0150.html.
2. ↑ Huang, Jianhui; Macdonald, Simon J. F.; Harrity, Joseph P. A. (2009). "A cycloaddition route to novel triazole boronic esters". Chem. Commun. (4): 436–438. doi:10.1039/b817052e. PMID 19137177.
3. ↑ Livingstone, E. S.; Maitland, A. (1991). "A high power, segmented metal, copper bromide laser". Measurement Science and Technology 2 (11): 1119. doi:10.1088/0957-0233/2/11/022. ISSN 0957-0233. Bibcode: 1991MeScT...2.1119L.
4. ↑ Breitinger, D. K.; Herrmann, W. A., eds (1999). Synthetic methods of Organometallic and Inorganic Chemistry. New York: Thieme Medical Publishers. ISBN 0-86577-662-8.
5. ↑ 5.0 5.1 Kenji Waizumi; Hideki Masuda; Hitoshi Ohtaki (1992). "X-ray structural studies of FeBr2·4H2O, CoBr2·4H2O, NiCl2·4H2O and CuBr2·4H2O. cis/trans selectivity in transition metal(II) dihalide tetrahydrate" (in en). Inorganica Chimica Acta 192 (2): 173-181. doi:10.1016/S0020-1693(00)80756-2.
6. ↑ Hope et al. J Chem Soc 5226 1960, Glemser & Sauer in Handbook of Preparative Inorganic Chemistry (Ed.Brauer) Academic Press Vol II p 1009 1965.
7. ↑ Helmholz, Lindsay (1947). "The Crystal Structure of Anhydrous Cupric Bromide". J. Am. Chem. Soc. 69 (4): 886–889. doi:10.1021/ja01196a046.
8. ↑ Conry, Rebecca R. (2006). "Encyclopedia of Inorganic Chemistry". Encyclopedia of Inorganic Chemistry (2nd ed.). John Wiley & Sons. doi:10.1002/0470862106.ia052. ISBN 978-0-470-86210-0.
9. ↑ King, L. Carroll; Ostrum, G. Kenneth (1964). "Selective Bromination with Copper(II) Bromide". J. Org. Chem. 29 (12): 3459–3461. doi:10.1021/jo01035a003.
10. ↑ Rodebaugh, Robert; Debenham, John S.; Fraser-Reid, Burt J.; Snyder, James P. (1999). "Bromination of Alkenyl Glycosides with Copper(II) Bromide and Lithium Bromide: Synthesis, Mechanism, and DFT Calculations". J. Org. Chem. 64 (5): 1758–1761. doi:10.1021/jo9718509. PMID 11674253.
11. ↑ McCoy, S.; Hanna, M.; Anderson, P.; McLennan, G.; Repacholi, M. (June 1996). "An evaluation of the copper-bromide laser for treating telangiectasia". Dermatol. Surg. 22 (6): 551–7. doi:10.1111/j.1524-4725.1996.tb00373.x. ISSN 1076-0512. PMID 8646471.
12. ↑ Davis P., Town G., Haywards H. A practical comparison of IPLs and the Copper Bromide Laser for photorejuvenation, acne and the treatment of vascular&pigmented lesions.
13. ↑ Diane Heppner The Focal Encyclopedia of Photography, Inc. Elsevier 20074th edition
14. ↑ George McKedy US Patent Application Publication, Pub.No.: US2010/0252779 A1
15. ↑ "Verification". https://www.mindat.org/min-40276.html.
16. ↑ "List of Minerals". 21 March 2011. https://www.ima-mineralogy.org/Minlist.htm.

* v
* t
* e

Copper compounds

Cu(0,I)|

* Cu5Si

Cu(I)|

* CuBr
* CuCN
* CuCl
* CuF
* CuH
* CuI
* Cu2C2
* Cu2Cr2O5
* Cu2O
* CuOH
* CuNO3
* Cu3P
* Cu2S
* CuSCN

Cu(I,II)|

* Cu3H4O8S2

Cu(II)|

* Cu(BF4)2
* CuBr2
* CuC2
* CuCO3
* Cu(CN)2
* Cu(ClO3)2
* CuCl2
* CuF2
* Cu(NO3)2
* Cu3(PO4)2
* Cu(N3)2
* CuO
* CuO2
* Cu(OH)2
* CuI2
* CuS
* CuSO4
* Cu3(AsO4)2

Cu(III)|

* K3CuF6
* Cu2O3

Cu(IV)|

* Cs2CuF6
* Rb2CuF6

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