Sodium bromide

Sodium bromide is a salt with the formula NaBr, widely used as an anticonvulsant and a sedative in the late 19th and early 20th centuries. Its action is due to the bromide ion (potassium bromide is equally effective). It is a high-melting white, crystalline solid that resembles sodium chloride. It is a widely used source of the bromide ion.

Additional recommended knowledge

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Principal chemical reactions

NaBr is widely used in organic synthesis as a nucleophile to convert organochlorine compounds to organobromine derivatives, which are more usefully (selectively) reactive.

NaBr + RCl → RBr + NaCl

• Sodium bromide can be used as a source of the chemical element bromine. This can be accomplished by bubbling chlorine gas through an aqueous solution of NaBr.
• As a source of HBr, NaBr is treated with a strong, non-volatile acid:

NaBr + H₃PO₄ → HBr + NaH₂PO₄

HBr can also be oxidized to Br₂ using MnO₂ or concentrated H₂SO₄.

Other applications

• as a hypnotic, anticonvulsant, and sedative in medicine. As a source of the bromide ion, which is pharmacologically active, it is equivalent to potassium bromide (see this article for more complete discussion of this topic).
• in photography
• to establish a bromide ion reserve in a bromine spa (hot tub) antimicrobial treatment regimen.

NaBr is sold under the brand name Sedoneural.

Safety

NaBr is harmful if swallowed or inhaled in large amounts, affecting the central nervous system, brain, and eyes (see potassium bromide). The compound causes irritation to the skin, eyes and respiratory system.

References