Strontium bromide

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Strontium bromide
Strontium-bromide-xtal-2011-Mercury-3D-balls.png
Names
IUPAC name
Strontium bromide
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.030.868
EC Number
  • 233-969-5
Properties
SrBr2
Molar mass 247.428 g/mol (anhydrous)
355.53 g/mol (hexahydrate)
Appearance white crystalline powder
Density 4.216 g/cm3 (anhydrous)
2.386 g/cm3 (hexahydrate)
Melting point 643 °C (1,189 °F; 916 K)
Boiling point 2,146 °C (3,895 °F; 2,419 K)
107 g/100 mL
Solubility soluble in alcohol
insoluble in ether
−86.6·10−6 cm3/mol
Structure
tetragonal[1]
Hazards
Main hazards Corrosive
NFPA 704 (fire diamond)
Flammability code 0: Will not burn. E.g. waterHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity code 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no codeNFPA 704 four-colored diamond
0
1
1
Related compounds
Other anions
strontium fluoride
strontium chloride
strontium iodide
Other cations
Beryllium bromide
Magnesium bromide
Calcium bromide
Barium bromide
Radium 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

Strontium bromide is a chemical compound with a formula SrBr2. At room temperature it is a white, odorless, crystalline powder. Strontium bromide imparts a bright red colour in a flame test, showing the presence of strontium ions. It is used in flares and also has some pharmaceutical uses.

Preparation[edit]

SrBr2 can be prepared from strontium hydroxide and hydrobromic acid.

Alternatively strontium carbonate can also be used as strontium source.

These reactions give hexahydrate of SrBr2, which decomposes to dihydrate at 89 °C. At 180 °C anhydrous SrBr2 is obtained.[2]

Structure[edit]

At room temperature, strontium bromide adopts a crystal structure with a tetragonal unit cell and space group P4/n. This structure is referred to as α-SrBr2 and is isostructural with EuBr2 and USe2. Around 920 K (650 °C), α-SrBr2 undergoes a first-order solid-solid phase transition to a much less ordered phase, β-SrBr2, which adopts the cubic fluorite structure. The beta phase of strontium bromide has a much higher ionic conductivity of about 1 S cm−1, comparable to that of molten SrBr2, due to extensive disorder in the bromide sublattice.[3] Strontium bromide melts at 930 K (657 °C).

See also[edit]

References[edit]

  1. ^ R. L. Sass; et al. (1963). "The crystal structure of strontium bromide". J. Phys. Chem. 67 (12): 2862. doi:10.1021/j100806a516.
  2. ^ Dale L. Perry, Sidney L. Phillips: Handbook of Inorganic Compounds. CRC Press, 1995, ISBN 978-0-8493-8671-8, (Strontium bromide, p. 387, at Google Books).
  3. ^ Hull, Stephen; Norberg, Stefan T.; Ahmed, Istaq; Eriksson, Sten G.; Mohn, Chris E. (2011). "High temperature crystal structures and superionic properties of SrCl2, SrBr2, BaCl2 and BaBr2". J. Solid State Chem. 184 (11): 2925–2935. doi:10.1016/j.jssc.2011.09.004.