Caesium bromide, is an ionic compound

Chemical compound

A chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...

 of caesium

Caesium

Caesium or cesium is the chemical element with the symbol Cs and atomic number 55. It is a soft, silvery-gold alkali metal with a melting point of 28 °C , which makes it one of only five elemental metals that are liquid at room temperature...

 and bromine

Bromine

Bromine ") is a chemical element with the symbol Br, an atomic number of 35, and an atomic mass of 79.904. It is in the halogen element group. The element was isolated independently by two chemists, Carl Jacob Löwig and Antoine Jerome Balard, in 1825–1826...

. It has simple cubic p-type cubic crystallic structure, comparable to that of caesium chloride

Caesium chloride

Caesium chloride is the inorganic compound with the formula CsCl. This colorless solid is an important source of caesium ions in a variety of applications. Its crystal structure forms a major structural type where each caesium ion is coordinated by 8 chlorine ions...

 type with space group

Space group

In mathematics and geometry, a space group is a symmetry group, usually for three dimensions, that divides space into discrete repeatable domains.In three dimensions, there are 219 unique types, or counted as 230 if chiral copies are considered distinct...

 Pmm and lattice constant

Lattice constant

The lattice constant [or lattice parameter] refers to the constant distance between unit cells in a crystal lattice. Lattices in three dimensions generally have three lattice constants, referred to as a, b, and c. However, in the special case of cubic crystal structures, all of the constants are...

 a = 0.42953 nm. Distance between Cs and Br atoms is 0.37198 nm.

Synthesis

It can be prepared via following reactions:

• Neutralization
  Neutralization
  In chemistry, neutralization, or neutralisation is a chemical reaction in which an acid and a base react to form a salt. Water is frequently, but not necessarily, produced as well. Neutralizations with Arrhenius acids and bases always produce water:Y and X represent a monovalent cation and anion...
  
  :

CsOH (aq) + HBr (aq) → CsBr (aq) + H₂O (l)

Cs₂(CO₃) (aq) + 2 HBr (aq) → 2 CsBr (aq) + H₂O (l) + CO₂ (g)

• Direct synthesis:

2 Cs (s) + Br₂ (g) → 2 CsBr (s)

The direct synthesis is a vigorous reaction of caesium with other halogens. Due to its expensiveness, it is not used for preparation.

Uses

Caesium bromide is sometimes used in optics as a beamsplitter component in wide-band spectrophotometers.

External links

• MSDS at Oxford University
• Physical data, Crystran PDF version, PDF version
• Caesium bromide at webelements.com
• Relaxed Excited States Origin and Structure in Lead-Doped Caesium Bromide
• IR transmission spectrum
• Ultra-violet photoabsorption measurements in alkali iodide and caesium bromide evaporated films