Sodium bromide

Crystal structure
	__ Na + __ Br -
Crystal system	cubic
Space group	Fm 3 m (No. 225)
Coordination numbers	Na [6], Br [6]
General
Surname	Sodium bromide
Ratio formula	NaBr
Brief description	colorless crystals
External identifiers / databases
EC number	231-599-9
ECHA InfoCard	100,028,727
PubChem	253881
Wikidata	Q15768
properties
Molar mass	102.89 g mol −1
Physical state	firmly
density	3.20 g cm −3 (20 ° C) ( anhydrate ) ; 2.176 g cm −3 (dihydrate) ;
Melting point	755 ° C
boiling point	1393 ° C
Vapor pressure	1.3 h Pa (806 ° C)
solubility	905 g l −1 (20 ° C) in water; 25 g l −1 (20 ° C) in ethanol;
Refractive index	1.642
safety instructions
GHS labeling of hazardous substances	no GHS pictograms
	no GHS pictograms
H and P phrases	H: no H-phrases
	P: no P-phrases
Toxicological data	3500 mg kg −1 ( LD 50 , rat , oral ) ; 0.414 mg l −1 ( LC 50 , fish , 96 h , median value) ; 10300 mg l −1 ( LC 50 , crustaceans , 48 h , median value) ; 9300 mg l −1 ( EC 50 , crustaceans , 48 h , median value) ; 8500 mg l −1 ( EC 50 , algae , 72 h , median value) ;
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Sodium bromide is the sodium salt of hydrogen bromide . It is a colorless solid with the formula NaBr.

Presentation and extraction

Sodium bromide can be made by reacting sodium hydroxide and hydrogen bromide :

{\ displaystyle \ mathrm {NaOH \ _ {(aq)} + \ HBr \ _ {(aq)} \ longrightarrow \ NaBr \ _ {(aq)} + \ H_ {2} O \ _ {(l)}} }

properties

Sodium bromide crystallizes in the sodium chloride structure . The aqueous solution reacts slightly acidic . A solution of 50 g of sodium bromide per liter of water at 20 ° C has a pH value of 5.4. Below 50.7 ° C, a dihydrate crystallizes from aqueous solution .

The standard enthalpy of formation of sodium bromide is ΔH _f⁰ = −360 kJ / mol.

The salt is very soluble in water. The solubility increases with increasing temperature.

solubility in water
temperature	in ° C	−20	0	20th	40	60	80	100	120
solubility	in g / 100 g H ₂ O	71.8	79.5	90.5	106	118	118.3	121.2	125.3

use

Sodium bromide can be used to produce elemental bromine on a laboratory scale. For this purpose, chlorine gas is fed into an aqueous solution of sodium bromide. This reaction can generally be used to detect soluble bromides .

{\ displaystyle \ mathrm {2 \ NaBr \ + \ Cl_ {2} \ \ longrightarrow 2 \ NaCl \ + \ Br_ {2}}}

Hydrogen bromide can be produced from sodium bromide on a laboratory scale . For this purpose, concentrated phosphoric acid is added dropwise to the solid at a slightly elevated temperature.

{\ displaystyle \ mathrm {2 \ NaBr \ + \ H_ {3} PO_ {4} \ {\ xrightarrow {\ Delta T}} \ 2 \ HBr \ uparrow + \ Na_ {2} HPO_ {4}}}

Other acids , for example dilute sulfuric acid , can also be used for this purpose , but here the reaction is often too difficult to control to generate a constant gas flow.

medicine

Sodium bromide was used as a sedative , particularly in the late 19th and early 20th centuries . Today it is no longer used as it can lead to bromism .

Individual evidence

↑ ^a ^b ^c ^d Sodium bromide data sheet (PDF) from Merck , accessed on January 18, 2011.

↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on sodium bromide in the GESTIS substance database of the IFA , accessed on December 19, 2019(JavaScript required) .

↑ ^a ^b Brockhaus ABC Chemie, FA Brockhaus Verlag Leipzig 1971, p. 920.

↑ Simao P. Pinho and Eugenia A. Macedo: Solubility of NaCl, NaBr, and KCl in Water, Methanol, Ethanol, and Their Mixed Solvents . Ed .: American Chemical Society. Portugal 2005, p. 30 .

↑ David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Index of Refraction of Inorganic Crystals, pp. 10-247.

^ ^A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1170.

↑ ^a ^b Yoffe, D .; Frim, R .; Ukeles, SD; Dagani, MJ; Barda, HJ; Benya, TJ; Sanders, DC: Bromine Compounds , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2013; doi : 10.1002 / 14356007.a04_405.pub2 .

↑ Jander, Blasius, Strähle: Introduction to the inorganic-chemical practical course , p. 281, 14th edition. Hirzel, Stuttgart 1995, ISBN 978-3-7776-0672-9 .

[merck-1] Sodium bromide data sheet (PDF) from Merck , accessed on January 18, 2011.

[GESTIS-2] ↑ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j Entry on sodium bromide in the GESTIS substance database of the IFA , accessed on December 19, 2019(JavaScript required) .

[ABC_Chemie-3] Brockhaus ABC Chemie, FA Brockhaus Verlag Leipzig 1971, p. 920.

[4] Simao P. Pinho and Eugenia A. Macedo: Solubility of NaCl, NaBr, and KCl in Water, Methanol, Ethanol, and Their Mixed Solvents . Ed .: American Chemical Society. Portugal 2005, p. 30 .

[CRC90_10_247-5] David R. Lide (Ed.): CRC Handbook of Chemistry and Physics . 90th edition. (Internet version: 2010), CRC Press / Taylor and Francis, Boca Raton, FL, Index of Refraction of Inorganic Crystals, pp. 10-247.

[HoWi-6] A ^b A. F. Holleman , E. Wiberg , N. Wiberg : Textbook of Inorganic Chemistry . 101st edition. Walter de Gruyter, Berlin 1995, ISBN 3-11-012641-9 , p. 1170.

[Ullmann-7] Yoffe, D .; Frim, R .; Ukeles, SD; Dagani, MJ; Barda, HJ; Benya, TJ; Sanders, DC: Bromine Compounds , in: Ullmanns Enzyklopädie der Technischen Chemie , Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2013; doi : 10.1002 / 14356007.a04_405.pub2 .

[8] Jander, Blasius, Strähle: Introduction to the inorganic-chemical practical course , p. 281, 14th edition. Hirzel, Stuttgart 1995, ISBN 978-3-7776-0672-9 .