Caesium fluoride

Other name: Cesium fluoride

CAS no. : 13400-13-0

EINECS no. : 236-487-3

Molecular formula: CsF

Molecular weight: 151.9039

Melting point: 682℃

Boiling point: 19.5 ° C at 760 mmHg

Solubility in water: 369 g / 100 mL (18℃)

The vapor pressure, 922 MMHG at 25°C


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Purity: 99.9%

Other content:

Lithium 0.001%

Sodium 0.01%

Potassium 0.01%

Rubidium 0.02%

Impurity content:

Aluminum ≤0.005%

Calcium ≤0.005%

Magnesium ≤0.005%

Iron ≤0.01%

Silicon ≤0.0005%

Lead ≤0.001%


Hazard: Toxic


Colorless cubic crystals. Hygroscopicity. At 18 ° C, 100 ml of water can dissolve 367 g, and 191 g can be dissolved in 100 ml of methanol at 15 ° C, which is insoluble in dioxane and pyridine. The refractive index (n18D) is 1.478±0.005. Irritating. Can cause burning.

Use :

Barium fluoride is a good base in organic chemistry, mainly because its fluoride ion is not strong nucleophilic. Studies have shown that the efficiency of Knoevenagel condensation of cesium fluoride is higher than that of potassium fluoride or sodium fluoride. In addition, since cesium fluoride is suitable for desiliconization protecting groups, it can convert many organosilicon compounds into organosilicon fluoro compounds and one carbanion by reacting with tetrahydrofuran or dimethylformamide.

In the Suzuki cross-coupling synthesis reaction, as a base, a positive substitution for biaryl; also as a nucleophile for the fluorination of primary halides and sulfonates in protic media such as tert-butyl or tert-amyl alcohol A catalyst for the reaction of a silicon enol ether with a carbonyl compound; for the efficient synthesis of a single crystal Dion-Jacobson phase CsLaTa2O7 for use in photocatalysis and superconductivity.

Barium fluoride can also be used to remove the silicon-based protecting group by a desilylation reaction.

Barium fluoride is also an important raw material for introducing fluorine into organic compounds. For example, cesium fluoride and hexafluoroacetone react to form perfluoroalkoxy sulfonium salts, which are stable below 60 °C and much more stable than the corresponding potassium and sodium salts. Since far infrared rays can easily pass through the crystals of barium fluoride, the crystals of barium fluoride can be used for infrared spectroscopy.


Crystal structure:

The crystal structure of cesium fluoride is a reverse rock salt type. The ruthenium ion in the crystal is larger than the chloride ion, and the cations in the lithium, sodium, potassium and cesium halides of the same group are smaller than the anion. In addition, in the crystal of yttrium fluoride, the yttrium ions are formed in the closest packing and the fluorine ions are embedded in the inside.

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