Copper(I) bromide is the
chemical compound
A chemical compound is a chemical substance composed of many identical molecules (or molecular entities) containing atoms from more than one chemical element held together by chemical bonds. A molecule consisting of atoms of only one element ...
with the
formula
In science, a formula is a concise way of expressing information symbolically, as in a mathematical formula or a ''chemical formula''. The informal use of the term ''formula'' in science refers to the general construct of a relationship betwe ...
CuBr. This white
diamagnetic
Diamagnetism is the property of materials that are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagn ...
solid adopts a polymeric structure akin to that for
zinc sulfide
Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various i ...
. The compound is widely used in the
synthesis of organic compounds and as a lasing medium in copper bromide lasers.
Preparation, basic properties, structure
The compound is white, although samples are often colored due to the presence of copper(II) impurities. The copper(I) ion also oxidizes easily in air. It is commonly prepared by the reduction of cupric salts with
sulfite in the presence of bromide.
[This report gives a procedure for generating CuBr: ] For example, the reduction of
copper(II) bromide with sulfite yields copper(I) bromide and
hydrogen bromide:
:2 CuBr
2 + H
2O + → 2 CuBr + + 2 HBr
CuBr is insoluble in most solvents due to its polymeric structure, which features four-coordinated, tetrahedral Cu centers interconnected by bromide ligands (ZnS structure). Upon treatment with
Lewis bases, CuBr converts to molecular
adduct
In chemistry, an adduct (; alternatively, a contraction of "addition product") is a product of a direct addition of two or more distinct molecules, resulting in a single reaction product containing all atoms of all components. The resultant is ...
s. For example, with
dimethyl sulfide, the colorless complex is formed:
:CuBr + S(CH
3)
2 → CuBr(S(CH
3)
2)
In this
coordination complex
A coordination complex is a chemical compound consisting of a central atom or ion, which is usually metallic and is called the ''coordination centre'', and a surrounding array of chemical bond, bound molecules or ions, that are in turn known as ' ...
, the copper is two-coordinate, with a linear geometry. Other soft ligands afford related complexes. For example,
triphenylphosphine gives CuBr(P(C
6H
5)
3), although this species has a more complex structure.
Thermal excitation of copper(I) bromide vapour yields a blue-violet emission which is of greater
saturation than known
copper(I) chloride
Copper(I) chloride, commonly called cuprous chloride, is the lower chloride of copper, with the formula CuCl. The substance is a white solid sparingly soluble in water, but very soluble in concentrated hydrochloric acid. Impure samples appear gr ...
emission.
Copper(I) bromide is hence an advantageous emitter in
pyrotechnic
Pyrotechnics is the science and craft of creating fireworks, but also includes safety matches, oxygen candles, explosive bolts (and other fasteners), parts of automotive airbags, as well as gas-pressure blasting in mining, quarrying, and demol ...
flames.
Applications in organic chemistry
In the
Sandmeyer reaction, CuBr is employed to convert diazonium salts into the corresponding
aryl bromides:
[
: + CuBr → ArBr + N2 + Cu+
The aforementioned complex CuBr(S(CH3)2) is widely used to generate organocopper reagents.][ Related CuBr complexes are ]catalyst
Catalysis () is the increase in rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recycles quick ...
s for atom transfer radical polymerization and copper-catalyzed cross-dehydrogenative couplings (CDC).
See also
Copper(II) bromide
References
External links
Web Elements
{{bromides
Bromides
Metal halides
Copper(I) compounds
Zincblende crystal structure