Barium bromide

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Barium bromide
Barium bromide
Identifiers
  • 10553-31-8 (anhydrous) checkY[PubChem]
  • 7791-28-8 (dihydrate) checkY[PubChem]
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.031.024 Edit this at Wikidata
EC Number
  • 234-140-0
UNII
Properties
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 (1,575 °F; 1,130 K)
Boiling point 1,835 °C (3,335 °F; 2,108 K)
92.2 g/100 mL (0°C)
-92.0·10−6 cm3/mol
Structure
orthorhombic, oP12
Pnma, No. 62
Thermochemistry
Std enthalpy of
formation (ΔfH⦵298)
 −181.1 kcal/mol
Hazards
Main hazards Toxic
Safety data sheet NIH BaBr
GHS pictograms GHS07: Harmful
GHS Signal word Warning
GHS hazard statements
 H302, H332
P261, P264, P270, P271, P301+312, P304+312, P304+340, P312, P330, P501
NFPA 704 (fire diamond)
3
0
0
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 otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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

Structure and properties[]

BaBr2 crystallizes in the lead chloride (cotunnite) motif, giving white orthorhombic crystals that are deliquescent.[1][2]

Coordination geometry of ions in barium bromide[1][3][4]
Ion Ba2+ Br− #1 Br− #2
Coordination sphere {BaBr9} {BrBa4} {BrBa3}
Ball-and-stick model Barium-bromide-xtal-Ba-coordination-3D-bs-17.png Barium-bromide-xtal-Br1-coordination-3D-bs-17.png Barium-bromide-xtal-Br2-coordination-3D-bs-17.png
Coordination number 9 4 3
Coordination geometry (7+2) coordination[5]
distorted tricapped trigonal prismatic 		distorted tetrahedral trigonal pyramidal

In aqueous solution BaBr2 behaves as a simple salt.

Solutions of barium bromide reacts with the sulfate salts to produce a solid precipitate of barium sulfate.

BaBr2 + SO42− → BaSO4 + 2 Br−

Similar reactions occur with oxalic acid, hydrofluoric acid, and phosphoric acid, giving solid precipitates of barium oxalate, fluoride, and phosphate, respectively.

Preparation[]

Barium bromide can be prepared by treating barium sulfide or barium carbonate with hydrobromic acid:

BaS + 2 HBr → BaBr2 + H2S
BaCO3 + 2 HBr → BaBr2 + CO2 + H2O

Barium bromide crystallizes from concentrated aqueous solution in its dihydrate , BaBr2·2H2O. Heating this dihydrate to 120 °C gives the anhydrous salt. [6]

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.[7]

Safety[]

Barium bromide, along with other water-soluble barium salts, is toxic.

References[]

  1. ^ Jump up to: a b Brackett, Elizabeth B.; Brackett, Thomas E.; Sass, Ronald L. (1963). "THE CRYSTAL STRUCTURES OF BARIUM CHLORIDE, BARIUM BROMIDE, AND BARIUM IODIDE". J. Phys. Chem. 67: 2132–2135. doi:10.1021/j100804a038.
  2. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 117–119. ISBN 978-0-08-037941-8.
  3. ^ "Information card for entry 1527183". Crystallography Open Database. Retrieved 2021-03-26.
  4. ^ "ICSD 15706 : ICSD Structure : Ba Br2". Cambridge Structural Database: Access Structures. Cambridge Crystallographic Data Centre. Retrieved 2021-03-26.
  5. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 382. ISBN 978-0-08-037941-8.
  6. ^ Patnaik, Pradyot (2003), Handbook of Inorganic Chemical Compounds, McGraw-Hill Professional, pp. 81–82, ISBN 978-0-07-049439-8, retrieved 2007-12-03
  7. ^ Sime, Ruth Lewin (1996), Lise Meitner: A Life in Physics, University of California Press, p. 233, ISBN 978-0-520-20860-5, retrieved 2007-12-03
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