Copper(II) bromide
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| Names | |
|---|---|
| Other names
Cupric bromide | |
| Identifiers | |
7789-45-9  | |
| 3D model (Jmol) | Interactive image |
| ChemSpider | 8395631 |
| ECHA InfoCard | 100.029.243 |
| PubChem | 24611 |
| |
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| Properties | |
| 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) |
| 55.7 g/100 mL (20 °C) | |
| Solubility in [[alcohol, acetone, ammonia]] | soluble |
| Solubility in [[benzene, ether, ethyl ether, sulfuric acid]] | insoluble |
| Structure | |
| monoclinic | |
| Hazards | |
| NFPA 704 | |
| US health exposure limits (NIOSH): | |
| 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 |
Nickel(II) bromide Copper(I) bromide Zinc bromide Cadmium bromide Mercury(II) fluoride |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
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| Infobox references | |
Copper(II) bromide (CuBr2) is a chemical compound. 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.
Synthesis
Copper(II) bromide can be obtained by combining copper oxide and hydrobromic acid:[4]
- CuO + 2HBr → CuBr2 + H2O.
Purification
Copper(II) bromide is purified by crystallisation twice from water, filtration to remove any CuBr and concentration under vacuum. This product is dehydrated using phosphorus pentoxide.[5]
Molecular and crystal structure
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'.[6] CuBr2 monomeric units are present in the gas phase at high temperature.[7]
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.[8]
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.[9]
Usage
Copper(II) bromide lasers produce pulsed yellow and green light and have been studied as a possible treatment for cutaneous lesions.[10] Experiments have also shown copper bromide treatment to be beneficial for skin rejuvenation.[11] It has been widely used in photography as its solution was used as the bleaching step for intensifying collodion and gelatin negatives.[12] Copper(II)bromide has also been proposed as a possible material in humidity indicator cards.[13]
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.
See also
References
- 1 2 3 "NIOSH Pocket Guide to Chemical Hazards #0150". National Institute for Occupational Safety and Health (NIOSH).
- ↑ 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.
- ↑ Livingstone, E. S.; Maitland, A. "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.
- ↑ 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.
- ↑ 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.
- ↑ Helmholz, Lindsay (1947). "The Crystal Structure of Anhydrous Cupric Bromide". J. Am. Chem. Soc. 69 (4): 886–889. doi:10.1021/ja01196a046.
- ↑ Conry, Rebecca R. (2006). "Copper: Inorganic & Coordination Chemistry". Encyclopedia of Inorganic Chemistry (2nd ed.). John Wiley & Sons. doi:10.1002/0470862106.ia052. ISBN 978-0-470-86210-0.
- ↑ King, L. Carroll; Ostrum, G. Kenneth (1964). "Selective Bromination with Copper(II) Bromide". J. Org. Chem. 29 (12): 3459–3461. doi:10.1021/jo01035a003.
- ↑ 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.
- ↑ 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. ISSN 1076-0512. PMID 8646471.
- ↑ 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.
- ↑ Diane Heppner The Focal Encyclopedia of Photography, Inc. Elsevier 20074th edition
- ↑ George McKedy US Patent Application Publication, Pub.No.: US2010/0252779 A1
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