Copper(II) bromide
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Other names
Cupric bromide
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Identifiers | |
7789-45-9 | |
ChemSpider | 8395631 |
Jmol 3D model | Interactive image |
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 | |
Vapor pressure | {{{value}}} |
Related compounds | |
Other anions
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Copper(II) fluoride Copper(II) chloride |
Other cations
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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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verify (what is ?) | |
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.[1]
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.[2] Producing yellow or green light, it is used in dermatological applications.
Contents
Synthesis
Copper(II) bromide can be obtained by combining copper oxide and hydrobromic acid:[3]
- 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.[4]
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'.[5] CuBr2 monomeric units are present in the gas phase at high temperature.[6]
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.[7]
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.[8]
Usage
Copper(II) bromide lasers produce pulsed yellow and green light and have been studied as a possible treatment for cutaneous lesions.[9] Experiments have also shown copper bromide treatment to be beneficial for skin rejuvenation.[10] It has been widely used in photography as its solution was used as the bleaching step for intensifying collodion and gelatin negatives.[11] Copper(II)bromide has also been proposed as a possible material in humidity indicator cards.[12]
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
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- ↑ 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.
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- ↑ 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