Copper (II) bromide

Crystal structure
	__ Cu 2+ __ Br -
General
Surname	Copper (II) bromide
other names	Copper dibromide
Ratio formula	CuBr 2
Brief description	Liquid black odorless crystals
External identifiers / databases
EC number	232-167-2
ECHA InfoCard	100.029.243
PubChem	24611
Wikidata	Q420370
properties
Molar mass	223.36 g mol −1
Physical state	firmly
density	4.71 g cm −3
Melting point	498 ° C
boiling point	900 ° C
solubility	very easily soluble in water (557 g / l at 20 ° C); soluble in ethanol and ethyl acetate; not soluble in benzene and diethyl ether;
safety instructions
H and P phrases	H: 302-314
	P: 280-305 + 351 + 338-310
MAK	0.1 mg / m 3
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Copper (II) bromide is a copper salt of hydrogen bromide with the ratio formula CuBr ₂ . Here copper has the +2 oxidation state .

presentation

Copper (II) bromide can be obtained from the elements .

{\ displaystyle \ mathrm {Cu + Br_ {2} \ longrightarrow CuBr_ {2}}}

Production from copper (II) oxide and hydrobromic acid or copper (II) chloride and boron (III) bromide is also possible .

{\ displaystyle \ mathrm {CuO + 2 \ HBr \ longrightarrow CuBr_ {2} + H_ {2} O}}

{\ displaystyle \ mathrm {3 \ CuCl_ {2} +2 \ BBr_ {3} \ longrightarrow 3 \ CuBr_ {2} +2 \ BCl_ {3}}}

properties

Copper (II) bromide is a greenish-black and hygroscopic solid that causes a green flame color . He is responsible for the green flame of a positive Beilstein sample , in which copper (II) bromide is formed after the above reaction. It crystallizes in the cadmium iodide structure. When heated, copper (II) bromide decomposes with the release of bromine to copper (I) bromide :

{\ displaystyle \ mathrm {2 \ CuBr_ {2} \ longrightarrow \ 2 \ CuBr \ + \ Br_ {2}}}

It has a monoclinic crystal structure with the space group C 2 / m (space group no. 12) , a = 7.18 Å, b = 3.46 Å, c = 7.14 Å, β = 121 ° 15 ′ and an enthalpy of formation of −139.7 kJ / mol. Template: room group / 12

solubility

Kuper (II) bromide is relatively soluble in water . At temperatures below 18.0 ° C, copper (II) bromide crystallizes out as a green tetrahydrate in the form of monoclinic prisms, above it in the anhydrous form as a black rhombohedron .

Temperature in ° C	0.0	5.75	9.9	15.0	20.0	25.0	30.1	34.8	50.0
Solubility in l / g	518	528	537	550	559	558	561	560	568

Diluted solutions are blue, concentrated solutions are green to dark brown.

use

In organic-chemical synthesis, ketones can be brominated with copper (II) bromide to form α-bromoketones .

literature

AF Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 102nd edition. Walter de Gruyter, Berlin 2007, ISBN 978-3-11-017770-1 .

Individual evidence

↑ ^a ^b ^c ^d ^e ^f ^g Entry on copper (II) bromide in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .
↑ ^a ^b ^c David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. CRC Press, 2009, ISBN 978-1-4200-9084-0 .
↑ ^a ^b Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 977.
↑ C. Rammelsberg: About bromide metals and their connections with ammonia . In: Annals of Physics . Vol. 131, No. 55 , 1842, pp. 237-253 ( Article ).
↑ Sydney Raymond Carter, Norman Joseph Lane Megson: A phase rule investigation of cupric bromide in aqueous and hydrobromic acid solutions . In: Journal of the Chemical Society . 1928, p. 2954-2967 , doi : 10.1039 / JR9280002954 .
^ JH Gladstone: On the Chemical Action of Water on Soluble Salts . In: Proceedings of the Royal Society of London . Vol. 9, 1857, pp. 66-70 , JSTOR : 111442 .
↑ L. Carroll King, G. Kenneth Ostrum: Selective Bromination with Copper (II) Bromide1 . In: The Journal of Organic Chemistry . tape 29 , no. December 12 , 1964, p. 3459-3461 , doi : 10.1021 / jo01035a003 .

[gestis-1] ↑ ^a ^b ^c ^d ^e ^f ^g Entry on copper (II) bromide in the GESTIS substance database of the IFA , accessed on January 8, 2020(JavaScript required) .

[crc-2] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. CRC Press, 2009, ISBN 978-1-4200-9084-0 .

[brauer-3] Georg Brauer (Ed.), With the collaboration of Marianne Baudler u a .: Handbook of Preparative Inorganic Chemistry. 3rd, revised edition. Volume II, Ferdinand Enke, Stuttgart 1978, ISBN 3-432-87813-3 , p. 977.

[4] C. Rammelsberg: About bromide metals and their connections with ammonia . In: Annals of Physics . Vol. 131, No. 55 , 1842, pp. 237-253 ( Article ).

[5] Sydney Raymond Carter, Norman Joseph Lane Megson: A phase rule investigation of cupric bromide in aqueous and hydrobromic acid solutions . In: Journal of the Chemical Society . 1928, p. 2954-2967 , doi : 10.1039 / JR9280002954 .

[6] JH Gladstone: On the Chemical Action of Water on Soluble Salts . In: Proceedings of the Royal Society of London . Vol. 9, 1857, pp. 66-70 , JSTOR : 111442 .

[7] L. Carroll King, G. Kenneth Ostrum: Selective Bromination with Copper (II) Bromide1 . In: The Journal of Organic Chemistry . tape 29 , no. December 12 , 1964, p. 3459-3461 , doi : 10.1021 / jo01035a003 .