Caesium chloride

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Caesium chloride

General
Other names	Cesium chloride
Molecular formula	CsCl
Molar mass	168.36 g/mol
Appearance	white solid
CAS number	[7647-17-8]
EINECS number	231-600-2
Properties
Density and phase	3.99 g/cm³, solid
Solubility in water	162 g/100 ml (1 °C)
In methanol In ethanol In acetone	33.7 g/100 ml Very soluble Insoluble
Melting point	645 °C
Boiling point	1295 °C
Structure
Coordination geometry	simple cubic
Crystal structure	see text
Thermodynamic data
Supplementary data page
Structure & properties	n, ε_r, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Related compounds
Other anions	Caesium fluoride Caesium bromide Caesium iodide
Other cations	Potassium chloride Rubidium chloride
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) Infobox disclaimer and references

Caesium chloride is the chemical compound with the formula CsCl. This colorless solid is an important source of caesium ions in a variety of applications. CsCl is also well known as a structural type.

1 Preparation
2 Crystal structure
3 Uses
4 Reference
5 External links

[edit] Preparation

Caesium chloride can be prepared by the reaction of caesium hydroxide or caesium carbonate with hydrochloric acid: the resulting salt is purified by recrystallization.

[edit] Crystal structure

The caesium chloride structure is composed of interlocking simple cubic lattices of anions and cations. It is the case that in a cubic 1:1 solid where one atom type is much larger than the other that the cesium chloride type lattice is obtained, it can be thought of as a combination of basketballs and golf balls packed in a cubic manner with the golf balls in the gaps between the basketballs. If the two atom types are similar in size (imagine field hockey balls packed with tennis balls) then in the cubic lattice the structure will be like that of sodium chloride.

[edit] Uses

Caesium chloride is used in the preparation of electrically conducting glasses. ^[1]

Radioisotopes of caesium chloride are used in nuclear medicine, including treatment of cancer. In the production of radioactive sources it is normal to choose a chemical form of the radioisotope which will not be dispersed with ease in the environment as a result of an accident where the source is smashed open. For instance radiothermal generators (RTGs) often use strontium titanate because it is insoluble in water. But for teletherapy sources the radioactive density (Ci in a given volume) needs to be very high, as a result it is not possible with any of the insoluble caesium compounds to create the source. As a result it is normal to use a thimble shaped can of radioactive caesium chloride to provide the active source in a teletherapy type radiotherapy unit. In Brazil such a source was stolen by scrap metal workers from a disused radiotherapy clinic, and serious injuries and deaths occurred as a result of external gamma exposure and internal exposure (the source was smashed open, releasing the water soluble cesium chloride). See the Goiânia accident for further details.

Cesium chloride (non radioactive) is also promoted as an alternative cancer therapy.^{[citation needed]} These claims are not accepted by the medical establishment.^{[citation needed]}