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Copper(II) bromide

Copper (II) bromide
Copper (II) bromide
Names
Other names
Cupric bromide
Identifiers
3D model (Jmol)
ChemSpider
ECHA InfoCard 100.029.243
PubChem CID
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
+685.5·10−6 cm3/mol
Structure
monoclinic
Hazards
NFPA 704
Flammability code 0: Will not burn. E.g., water Health code 2: Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury. E.g., chloroform Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
US health exposure limits (NIOSH):
PEL (Permissible)
 TWA 1 mg/m3 (as Cu)
REL (Recommended)
 TWA 1 mg/m3 (as Cu)
IDLH (Immediate danger)
 TWA 100 mg/m3 (as Cu)
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).
YesY  (what is YesYN ?)
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.

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. Producing yellow or green light, it is used in dermatological applications.

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

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.

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'. CuBr2 monomeric units are present in the gas phase at high temperature.

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.

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.

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


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