Strontium bromide

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Strontium bromide is a chemical compound with a formula SrBr₂. At room temperature it is a white, odorless, crystalline powder. Strontium bromide burns bright red in a flame test. It is used in flares and also has some pharmaceutical uses.

Video Strontium bromide

Preparation

SrBr₂ can be prepared from strontium hydroxide and hydrobromic acid.

${\displaystyle \mathrm {Sr(OH)_{2}+2\ HBr\longrightarrow SrBr_{2}+2\ H_{2}O} }$

Alternatively strontium carbonate can also be used as strontium source.

${\displaystyle \mathrm {SrCO_{3}+2\ HBr\longrightarrow SrBr_{2}+H_{2}O+CO_{2}\uparrow } }$

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

Maps Strontium bromide

Structure

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 ?-SrBr₂ and is isostructural with EuBr₂ and USe₂. Around 920 K (650 °C), ?-SrBr₂ undergoes a first-order solid-solid phase transition to a much less ordered phase, ?-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. Strontium bromide melts at 930 K (657 °C).

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See also

• Strontium chloride

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References

• http://www.webelements.com/

Source of article : Wikipedia