Barium bromide

Barium bromide is the chemical compound with the formula BaBr₂. Like barium chloride, it dissolves well in water and is toxic in aqueous solution.

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Structure and properties

BaBr₂ crystallizes in a lead chloride motif, giving white orthorhombic crystals which are deliquescent.^[2] In aqueous solution BaBr₂ behaves as a simple salt.

Barium bromide reacts with the sulfate ion from sulfuric acid to produce a precipitate of barium sulfate.

BaBr₂(aq) + SO₄^2- → BaSO₄(s) + 2 Br^-(aq)

Similar reactions occur with oxalic acid, hydrofluoric acid, and phosphoric acid.

Preparation

Barium bromide can be prepared from barium sulfide or barium carbonate via reaction with hydrobromic acid to give hydrated barium bromide.

BaS + HBr → BaBr₂ + H₂S

BaCO₃ + HBr → BaBr₂ + CO₂ + H₂O

Barium bromide can be crystallized out from the solution in its dihydrate form, BaBr₂·2H₂O, which gives the anhydrous form upon heating to 120 °C.^[3]

Uses

Barium bromide is a precursor to chemicals used in photography and to other bromides.
Historically, barium bromide was used to purify radium in a process of fractional crystallization devised by Marie Curie. Since radium precipitates preferentially in a solution of barium bromide, the ratio of radium to barium in the precipitate would be higher than the ratio in the solution.^[4]

Safety

Barium bromide, along with other water-soluble barium salts, is toxic and can cause severe poisoning if ingested.

References

1. ^ https://fscimage.fishersci.com/msds/10358.htm
2. ^ Brackett, Elizabeth B.; Breackett, Thomas E. & Sass, Ronald L. (December), , , vol. 67 (published 1963), pp. 2132, . Retrieved on 2007-12-03
3. ^ Patnaik, Pradyot, , McGraw-Hill Professional, pp. 81-82, ISBN 0070494398, . Retrieved on 2007-12-03
4. ^ Sime, Ruth Lewin, , University of California Press, pp. 233, ISBN 0520208609, . Retrieved on 2007-12-03