Sodium bromide

Sodium bromide

Names
IUPAC name Sodium bromide
Identifiers
CAS Number	anhydrous: 7647-15-6 Y dihydrate: 13466-08-5 N
3D model (JSmol)	anhydrous: Interactive image
ChEMBL	anhydrous: ChEMBL1644694 Y
ChemSpider	anhydrous: 22712 Y
ECHA InfoCard	100.028.727
PubChem CID	anhydrous: 253881
RTECS number	anhydrous: VZ3150000
UNII	anhydrous: LC1V549NOM Y
CompTox Dashboard (EPA)	anhydrous: DTXSID3034903
InChI InChI=1S/BrH.Na/h1H;/q;+1/p-1 Y Key: JHJLBTNAGRQEKS-UHFFFAOYSA-M Y anhydrous: InChI=1/BrH.Na/h1H;/q;+1/p-1 Key: JHJLBTNAGRQEKS-REWHXWOFAR
SMILES anhydrous: [Na+].[Br-]
Properties
Chemical formula	NaBr
Molar mass	102.894 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, pyridine, hydrazine, SO2 Insoluble in acetone, acetonitrile[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]
Magnetic susceptibility (χ)	−41.0·10−6 cm3/mol
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
Heat capacity (C)	51.4 J/(mol·K)[1]
Std molar entropy (S⦵298)	86.82 J/(mol·K)[1]
Std enthalpy of formation (ΔfH⦵298)	−361.41 kJ/mol[1]
Gibbs free energy (ΔfG⦵)	−349.3 kJ/mol[1]
Pharmacology
Legal status	AU: S4 (Prescription only) /S5
Hazards
NFPA 704 (fire diamond)	[6] 2 0 0
Flash point	800 °C (1,470 °F; 1,070 K)
Lethal dose or concentration (LD, LC):
LD50 (median dose)	3500 mg/kg (rats, oral)
Safety data sheet (SDS)	External MSDS
Related compounds
Other anions	Sodium fluoride Sodium chloride Sodium iodide Sodium astatide
Other cations	Lithium bromide Potassium bromide Rubidium bromide Caesium bromide Francium bromide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) 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

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) crystallize out of water solution below 50.7 °C.^[8]

NaBr 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

Sodium bromide is the most useful inorganic bromide in industry.^[7] It is also used as a catalyst in TEMPO-mediated oxidation reactions.^[9]

Medicine

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. In 1975, bromides were removed from drugs in the U.S. such as Bromo-Seltzer due to toxicity.^[10]

Preparation of other bromine compounds

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

Sodium bromide is used in conjunction with chlorine as a disinfectant for hot tubs and swimming pools.

Petroleum industry

Because of its high solubility in water (943.2 g/L or 9.16 mol/L, at 25 °C) sodium bromide is used to prepare dense drilling fluids used in oil wells to compensate a possible overpressure arising in the fluid column and to counteract the associated trend to blow out. The presence of the sodium cation also causes the bentonite added to the drilling fluid to swell, while the high ionic strength induces bentonite flocculation.

Safety

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

External links

Wikimedia Commons has media related to Sodium bromide.

• Information about NaBr.
• Bromide Poisoning in Angola