Sodium bromide

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Sodium bromide
3D model of sodium bromide
Sodium bromide powder
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 BrNa
Molar mass 102.89 g mol−1
Appearance White powder, hygroscopic
Density 3.21 g/cm3 (anhydrous)
2.18 g/cm3 (dihydrate)
Melting point 747 °C (1,377 °F; 1,020 K)
(anhydrous)
36 °C (97 °F; 309 K)
(dihydrate) decomposes[3]
Boiling point 1,390 °C (2,530 °F; 1,660 K) [3]
Solubility in water 71.35 g/100 mL (−20 °C)
79.52 g/100 mL (0 °C)
94.32 g/100 mL (25 °C)[1]
104.9 g/100 mL (40 °C)
116.2 g/100 mL (100 °C)[2]
Solubility Soluble in alcohol, liquid ammonia, acetone, pyridine, hydrazine, acetonitrile, SO2, amine[1]
Solubility in methanol 17.3 g/100 g (0 °C)
16.8 g/100 g (20 °C)
16.1 g/100 g (40 °C)
15.3 g/100 g (60 °C)[1]
Solubility in ethanol 2.45 g/100 g (0 °C)
2.32 g/100 g (20 °C)
2.29 g/100 g (30 °C)
2.35 g/100 g (70 °C)[1]
Solubility in formic acid 19.3 g/100 g (18 °C)
19.4 g/100 g (25 °C)[1]
Solubility in glycerol 38.7 g/100 g (20 °C)[1]
Solubility in dimethylformamide 3.2 g/100 g (10.3 °C)[1]
Vapor pressure 1 torr (806 °C)
5 torr (903 °C)[3]
Thermal conductivity 5.6 W/m·K (150 K)[4]
Refractive index (nD) 1.6428 (24 °C)
nKrF = 1.8467 (24 °C)
nHe–Ne = 1.6389 (24 °C)[5]
Viscosity 1.42 cP (762 °C)
1.08 cP (857 °C)
0.96 cP (937 °C)[1]
Structure
Crystal structure Cubic
Lattice constant a = 5.97 Å[4]
Thermochemistry
Specific
heat capacity
C
51.4 J/mol·K[1]
Std molar
entropy
So298
86.82 J/mol·K[1]
Std enthalpy of
formation
ΔfHo298
−361.41 kJ/mol[1]
Gibbs free energy ΔG −349.3 kJ/mol[1]
Hazards
MSDS External MSDS
EU Index Not listed
R-phrases R36
S-phrases (S2), S24/25, S46
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
Flash point 800 °C (1,470 °F; 1,070 K)
LD50 3500 mg/kg (rats, oral)
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.[7]

Synthesis, structure, reactions[edit]

NaBr crystallizes in the same cubic motif as NaCl, NaF and NaI. The anhydrous salt crystallizes above 50.7 °C.[7] Dihydrate salts (NaBr·2H2O) begins to anhydrous at 50.7 °C in water solution.[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.[7]

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.[8]

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]

Sodium bromide 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.[6] 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 c d e f g h i j k l http://chemister.ru/Database/properties-en.php?dbid=1&id=714
  2. ^ a b Seidell, Atherton; Linke, William F. (1919). Solubilities of Inorganic and Organic Compounds (2nd ed.). D. Van Nostrand Company. 
  3. ^ a b c Pradyot, Patnaik (2003). Handbook of Inorganic Chemicals. The McGraw-Hill Companies, Inc. ISBN 0-07-049439-8. 
  4. ^ a b "Sodium Bromide (NaBr)". http://www.korth.de. Korth Kristalle GmbH. Retrieved 2014-06-11. 
  5. ^ Polyanskiy, Mikhail. "Refractive index of NaBr (Sodium bromide) - Li". http://www.refractiveindex.info. Retrieved 2014-06-11. 
  6. ^ a b "Sodium bromide MSDS" (PDF). http://www.sciencelab.com. Sciencelab.com, Inc. 2013-05-21. Retrieved 2014-06-11. 
  7. ^ 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
  8. ^ "Bromide: Potassium & Sodium". http://www.canine-epilepsy.com. Canine-Epilepsy Resources. 2011-05-31. Retrieved 2014-06-11. 

External links[edit]