Barium bromide

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Barium bromide
Identifiers
CAS number 10553-31-8 N, (anhydrous)
7791-28-8 (dihydrate)
ChemSpider 59728 YesY
Jmol-3D images Image 1
Properties
Molecular formula BaBr2 (anhydrous)

BaBr2·2H2O (dihydrate)

Molar mass 297.14 g/mol
Appearance White solid
Density 4.78 g/cm3 (anhydrous)
3.58 g/cm3 (dihydrate)
Melting point 857 °C
Boiling point 1835 °C
Solubility in water 92.2 g/100 mL (0°C)
Structure
Crystal structure orthorhombic, oP12, SpaceGroup = Pnma, No. 62
Thermochemistry
Std enthalpy of
formation
ΔfHo298
−181.1 kcal/mol
Hazards
EU classification Harmful (Xn)
R-phrases R20, R22
S-phrases S28[1]
Related compounds
Other anions Barium fluoride
Barium chloride
Barium iodide
Other cations Beryllium bromide
Magnesium bromide
Calcium bromide
Strontium bromide
Radium bromide
Lead 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

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

Structure and properties[edit]

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) + SO42- → BaSO4(s) + 2 Br-(aq)

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

Preparation[edit]

Barium bromide can be prepared from barium sulfide or barium carbonate via reaction with hydrobromic acid to give hydrated barium bromide. This happens over a short period of time

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[edit]

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[edit]

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

References[edit]

  1. ^ https://fscimage.fishersci.com/msds/10358.htm
  2. ^ Brackett, Elizabeth B.; Breackett, Thomas E.; Sass, Ronald L. (December), "The Crystal Structures of Barium Chloride, Barium Bromide, and Barium Iodide." (– Scholar search), The Journal of Physical Chemistry 67 (published 1963), p. 2132, retrieved 2007-12-03  [dead link]
  3. ^ Patnaik, Pradyot (2003), Handbook of Inorganic Chemical Compounds, McGraw-Hill Professional, pp. 81–82, ISBN 0-07-049439-8, retrieved 2007-12-03 
  4. ^ Sime, Ruth Lewin (1996), Lise Meitner: A Life in Physics, University of California Press, p. 233, ISBN 0-520-20860-9, retrieved 2007-12-03