Barium bromide
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Identifiers | |
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3D model (JSmol)
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ChemSpider | |
ECHA InfoCard | 100.031.024 ![]() |
EC Number |
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PubChem CID
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UNII | |
CompTox Dashboard (EPA)
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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 | ![]() |
GHS Signal word | Warning |
GHS hazard statements
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H302, H332 |
P261, P264, P270, P271, P301+312, P304+312, P304+340, P312, P330, P501 | |
NFPA 704 (fire diamond) | ![]()
3
0
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Related compounds | |
Other anions
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Barium fluoride Barium chloride Barium iodide |
Other cations
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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]
Ion | Ba2+ | Br− #1 | Br− #2 |
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Coordination sphere | {BaBr9} | {BrBa4} | {BrBa3} |
Ball-and-stick model | ![]() |
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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[]
- ^ 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.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. pp. 117–119. ISBN 978-0-08-037941-8.
- ^ "Information card for entry 1527183". Crystallography Open Database. Retrieved 2021-03-26.
- ^ "ICSD 15706 : ICSD Structure : Ba Br2". Cambridge Structural Database: Access Structures. Cambridge Crystallographic Data Centre. Retrieved 2021-03-26.
- ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. p. 382. ISBN 978-0-08-037941-8.
- ^ Patnaik, Pradyot (2003), Handbook of Inorganic Chemical Compounds, McGraw-Hill Professional, pp. 81–82, ISBN 978-0-07-049439-8, retrieved 2007-12-03
- ^ 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
- Bromides
- Metal halides
- Barium compounds