WebElements Periodic Table of the Elements | Caesium

Caesium compounds: caesium fluoride

The caesium in caesium fluoride formally is in the oxidation state 1.

Caesium fluoride

Formula as often written: CsF
Hill system formula: Cs₁F₁
CAS registry number: [13400-13-0]
Formula weight: 151.904
Class: fluoride

Synonyms

caesium fluoride
caesium(I) fluoride
cesium fluoride
cesium(I) fluoride

Physical properties

Colour: white
Appearance: crystalline solid
Melting point: 703°C
Boiling point: 1231°C
Density: 4640 kg m^-3

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Element analysis

Element percentages for the elements in caesium fluoride
Element	%
Cs	87.49
F	12.51

Synthesis

One way to make caesium fluoride is to react the hydroxide with hydrofluoric acid. The resulting salt can then be purified by recrystallization.

CsOH(aq) + HF(aq) → CsF(aq) + H₂O(l)

Another way to make caesium(I) fluoride is to react the carbonate with CsHF₂. The resulting salt can then be purified by recrystallization.

Cs₂CO₃(aq) + 2CsHF₂(aq) → 4CsF(aq) + H₂O(l) + CO₂(g)

While not a normal route of preparation because of the expense, caesium metal reacts vigorously with all the halogens to form caesium halides. So, it burns with fluorine, F₂, to form caesium(I) fluoride, CsF.

2Cs(s) + F₂(g) → 2CsF(s)

Solid state structure

Geometry of caesium: 6 coordinate: octahedral
Prototypical structure: NaCl (rock salt)

Crystal structure of caesium fluoride

Isotope pattern

What follows is the calculated isotope pattern for the CsF unit with the most intense ion set to 100%.

Formula: Cs₁F₁

mass  %
152 100.0 __________________________________________________

References

The data on these compounds pages are assembled and adapted from the primary literature and several other sources including the following.

R.T. Sanderson in Chemical Periodicity, Reinhold, New York, USA, 1960.
N.N. Greenwood and A. Earnshaw in Chemistry of the Elements, 2nd edition, Butterworth, UK, 1997.
F.A. Cotton, G. Wilkinson, C.A. Murillo, and M. Bochmann, in Advanced Inorganic Chemistry, John Wiley & Sons, 1999.
A.F. Trotman-Dickenson, (ed.) in Comprehensive Inorganic Chemistry, Pergamon, Oxford, UK, 1973.
R.W.G. Wyckoff, in Crystal Structures, volume 1, Interscience, John Wiley & Sons, 1963.
A.R.West in Basic solid state chemistry Chemistry, John Wiley & Sons, 1999.
A.F. Wells in Structural inorganic chemistry, 4th edition, Oxford, UK, 1975.
J.D.H. Donnay, (ed.) in Crystal data determinative tables, ACA monograph number 5, American Crystallographic Association, USA, 1963.
D.R. Lide, (ed.) in Chemical Rubber Company handbook of chemistry and physics, CRC Press, Boca Raton, Florida, USA, 77th edition, 1996.
J.W. Mellor in A comprehensive treatise on inorganic and theoretical chemistry, volumes 1-16, Longmans, London, UK, 1922-1937.
J.E. Macintyre (ed.) in Dictionary of inorganic compounds, volumes 1-3, Chapman & Hall, London, UK, 1992.