Strontium bromide

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.[2]

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. The compound's structure was initially erroneously interpreted as being of the PbCl₂ type,[3] but this was later corrected.[4][1]

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.[1] Strontium bromide melts at 930 K (657 °C).

• 
  Space-filling model of the packing of Sr²⁺ and Br⁻ ions in α-SrBr₂
• 
  Distorted square antiprismatic coordination geometry of crystallographically independent strontium atom number 1
• 
  Square antiprismatic coordination geometry of strontium number 2
• 
  Flattened tetrahedral coordination geometry of bromine number 1
• 
  Distorted tetrahedral coordination geometry of bromine number 2
• 
  Tetrahedral coordination geometry of bromine number 3
• 
  Tetrahedral coordination geometry of bromine number 4

• Strontium chloride

• http://www.webelements.com/