Sodium bromide

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Sodium bromide
Sodium bromide
Sodium bromide
Identifiers
CAS number 7647-15-6 YesY, 13466-08-5 (dihydrate) YesY
PubChem 253881
ChemSpider 22712 YesY
UNII LC1V549NOM YesY
ChEMBL CHEMBL1644694 N
RTECS number VZ3150000
Jmol-3D images Image 1
Properties
Molecular formula NaBr
Molar mass 102.894 g/mol
Appearance White powder
Density 3.21 g/cm3 (anhydrous)
2.18 g/cm3 (dihydrate)
Melting point 747 °C (anhydrous)
36 °C (dihydrate)
Boiling point 1396 °C
Solubility in water 90.5 g/100 mL (20 °C) 121.0 g/100 mL (100 °C)
Solubility in methanol 16.7 g/100 mL
Refractive index (nD) 1.6459
Thermochemistry
Std molar
entropy
So298
84 J·mol−1·K−1[1]
Std enthalpy of
formation
ΔfHo298
−360 kJ·mol−1[1]
Hazards
MSDS External MSDS
EU Index Not listed
Flash point 800 °C (1,470 °F; 1,070 K)
LD50 3500 mg/kg
Related compounds
Other anions Sodium fluoride
Sodium chloride
Sodium iodide
Other cations Lithium bromide
Potassium bromide
Rubidium bromide
Caesium bromide
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 N (verify) (what is: YesY/N?)
Infobox references

Sodium bromide is an inorganic compound with the formula NaBr. It is a high-melting white, crystalline solid that resembles sodium chloride. It is a widely used source of the bromide ion and has many applications.[2]

Synthesis, structure, reactions[edit]

NaBr crystallizes in the same cubic motif as NaCl, NaF and NaI. The anhydrous salt crystallizes above 50.7 °C.[2]

It is produced by treating sodium hydroxide with hydrogen bromide.

Sodium bromide can be used as a source of the chemical element bromine. This can be accomplished by treating an aqueous solution of NaBr with chlorine gas:

2 NaBr + Cl2 → Br2 + 2 NaCl

Applications[edit]

Sodium bromide is the most useful inorganic bromide in industry.[2]

Medicine[edit]

Also known as Sedoneural, sodium bromide has been used as a hypnotic, anticonvulsant, and sedative in medicine, widely used as an anticonvulsant and a sedative in the late 19th and early 20th centuries. Its action is due to the bromide ion, and for this reason potassium bromide is equally effective.[3]

Preparation of other bromine compounds[edit]

Sodium bromide is widely used for the preparation of other bromides in organic synthesis and other areas. It is a source of the bromide nucleophile to convert alkyl chlorides to more reactive alkyl bromides by the Finkelstein reaction:

NaBr + RCl → RBr + NaCl (R = alkyl)

Once a large need in photography, but now shrinking, the photosensitive salt silver bromide is prepared using NaBr.

Disinfectant[edit]

NaBr is used in conjunction with chlorine as a disinfectant for swimming pools.

Petroleum industry[edit]

Sodium bromide is used to prepare dense fluids used in oil wells.

Safety[edit]

NaBr has a very low toxicity with an oral LD50 estimated at 3.5 g/kg for rats.[4] However, this is a single-dose value. Bromide ion is a cumulative toxin with a relatively long half life (in excess of a week in humans): see potassium bromide.

References[edit]

  1. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A23. ISBN 0-618-94690-X. 
  2. ^ a b c Michael J. Dagani, Henry J. Barda, Theodore J. Benya, David C. Sanders "Bromine Compounds" in Ullmann's Encyclopedia of Industrial Chemistry Wiley-VCH, Weinheim, 2000. doi:10.1002/14356007.a04_405
  3. ^ Bromide
  4. ^ MSDS

External links[edit]