Barium bromide

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Barium bromide
Identifiers
CAS number [10553-31-8]
Properties
Molecular formula BaBr2 (anhydrous)

BaBr2·2H2O (dihydrate)
Molar mass 297.14 g/mol
Appearance White solid
Density 4.78 g/cm3, anhydrous solid
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
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 Calcium bromide
Strontium bromide
Lead bromide
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and 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.

Contents

[edit] 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) + SO42- → BaSO4(s) + 2 Br-(aq)

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

[edit] 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]

[edit] 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]

[edit] Safety

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

[edit] References

  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.”, The Journal of Physical Chemistry, vol. 67 (published 1963), pp. 2132, <http://pubs.acs.org/cgi-bin/abstract.cgi/jpchax/1963/67/i10/f-pdf/f_j100804a038.pdf?sessid=6006l3>. Retrieved on 2007-12-03 
  3. ^ Patnaik, Pradyot, Handbook of Inorganic Chemical Compounds, McGraw-Hill Professional, pp. 81-82, ISBN 0070494398, <http://books.google.com/books?id=Xqj-TTzkvTEC&pg=RA1-PA81&dq=%22barium+bromide%22+subject:%22Chemistry,+Inorganic%22&ei=ondUR4ScB4yKpwLHj9HCBg&sig=IRCDxRhFJfMmES20I4dngv237Uo>. Retrieved on 2007-12-03 
  4. ^ Sime, Ruth Lewin, Lise Meitner: A Life in Physics, University of California Press, pp. 233, ISBN 0520208609, <http://books.google.com/books?id=uPzZQzx-mkcC&pg=PA233&dq=%22barium+bromide%22+radium&as_brr=3&ei=73pUR9rFJ474pwLC_IGLDw&sig=yB0nytEH5qWeIakFCgzNUJOUK1E>. Retrieved on 2007-12-03 
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