Overview

Caesium fluoride (cesium fluoride in North America), is an ionic compound usually found as a hygroscopic white solid. It is more soluble and more readily dissociated than sodium fluoride or potassium fluoride. CsF is commercially available – on a lab scale it costs around $50 per 100g (Synquest (http://www.synquestlabs.com/catalog/catalog.html)), cheaper than RbF. It is available in anhydrous form, and if water has been absorbed it is easy to dry by heating at 100 °C for two hours in vacuo (http://en.wiktionary.org/wiki/Vacuum)^[3]. It is therefore a useful, less hygroscopic alternative to tetra-n-butylammonium fluoride (TBAF) and TAS-fluoride when anhydrous "naked" fluoride ion is needed. Like all soluble fluorides, it is mildly basic. Contact with acid should be avoided, as this forms highly toxic/corrosive hydrofluoric acid. Dissociation in chemistry and biochemistry is a general process in which complexes, molecules, or salts separate or split into smaller molecules, ions, or radicals, usually in a reversible manner. ... A fluoride ion is the ionic form of fluorine. ... link title Headline text Bold textItalic textItalic textInsert non-formatted text hereInsert non-formatted text hereInsert non-formatted text hereInsert non-formatted text hereInsert non-formatted text here--220. ... A hygroscopic or hydroscopic substance is a substance that absorbs water readily from its surroundings. ... A fluoride ion is the ionic form of fluorine. ... A fluoride ion is the ionic form of fluorine. ... A base is: in mathematics: A number that is raised to a power, or base of an exponential function. ... An acid (often represented by the generic formula AH) is typically a water-soluble, sour-tasting chemical compound. ... Hydrofluoric acid is a highly corrosive solution of the chemical compound hydrogen fluoride in water. ...

Chemical Properties

Caesium fluoride reacts usually as a source of fluoride ion, F^-. It therefore undergoes all of the usually reactions associated with soluble fluorides such as potassium fluoride, for example: A fluoride ion is the ionic form of fluorine. ... A fluoride ion is the ionic form of fluorine. ...

2 CsF(aq) + CaCl₂(aq) —→ 2 CsCl(aq) + CaF₂(s) Drinking water This article focuses on water as we experience it every day. ... Overview Calcium chloride is a chemical compound of calcium and chlorine. ... Drinking water This article focuses on water as we experience it every day. ... Drinking water This article focuses on water as we experience it every day. ... Calcium fluoride (CaF2) is an insoluble ionic compound of calcium and fluorine. ... A solid is a state of matter, characterized by a definite volume and a definite shape (i. ...

Being highly dissociated it is quite reactive as a fluoride source under anhydrous conditions too, and it will react with electron-deficient aryl chlorides to form aryl fluorides (halex reaction). Due to the strength of the Si-F bond, fluoride ion is useful for desilylation reactions (removal of Si groups) in organic chemistry; caesium fluoride is an excellent source of anhydrous fluoride for such reactions (see uses below). As with other soluble fluorides, CsF is moderately basic, due to the fact that HF is a weak acid. The low nucleophilicity of fluoride means it can be a useful base in organic chemistry (see uses below). A fluoride ion is the ionic form of fluorine. ... In chemistry, an aromatic molecule is one in which electrons are free to cycle around circular arrangements of atoms, which are alternately singly and doubly bonded to one another. ... General Name, Symbol, Number silicon, Si, 14 Series metalloid Group, Period, Block 14 (IVA), 3, p Density, Hardness 2330 kg/m3, 6. ... General Name, Symbol, Number Fluorine, F, 9 Series Halogens Group, Period, Block 17 (VIIA), 2, p Density, Hardness 1. ... A fluoride ion is the ionic form of fluorine. ... Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds. ... A fluoride ion is the ionic form of fluorine. ... Hydrofluoric acid is a highly corrosive solution of the chemical compound hydrogen fluoride in water. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ...

Preparation

Caesium fluoride may be prepared by the action of hydrofluoric acid on caesium hydroxide or caesium carbonate, followed by removal of water. Hydrofluoric acid is a highly corrosive solution of the chemical compound hydrogen fluoride in water. ... Caesium hydroxide, (CsOH) is a chemical compound consisting of an atom of Caesium and a hydroxide group. ...

Uses

Caesium fluoride is a useful base in organic chemistry, due the fact that fluoride ion is largely unreactive as a nucleophile. It is reported that CsF gives higher yields in Knoevenagel condensation reactions than KF or NaF^[4]. Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds. ... A fluoride ion is the ionic form of fluorine. ... An ion is an elementary particle or system of elementary particles with a net electric charge. ... In chemistry, a nucleophile (literally nucleus lover) is a reagent which is attracted to centres of positive charge. ... The Knoevenagel condensation reaction is a organic reaction named after Emil Knoevenagel. ... A fluoride ion is the ionic form of fluorine. ...

Removal of silicon groups (desilylation) is a major application for CsF in the laboratory, as its anhydrous nature allows clean formation of [[|water_(molecule)|water]]-sensitive intermediates. Caesium fluoride in THF or DMF can attack a wide variety of organosilicon compounds to produce an organosilicon fluoride and a carbanion, which can then react with electrophiles^[3], for example^[5]: Liquids and solids (powders) are anhydrous if they are without water, i. ... Tetrahydrofuran, also known as THF, hydrofuran, oxolane, oxacyclopentane, or furanidine, is a heterocyclic organic compound. ... Dimethylformamide, also known under the names N,N-dimethylformamide and DMF, is a clear, water-miscible liquid and common solvent that is often used in chemical reactions. ... A carbanion is an anion in which carbon has an unshared pair of electrons and bears a negative charge usually with three substituents for a total of eight valence electrons). ... In chemistry, an electrophile (literally electron-lover) is a reagent attracted to electrons that participates in a chemical reaction by accepting an electron pair in order to bond to a substance. ... Download high resolution version (1950x350, 11 KB)An example of a desilylation reaction initiated by CsF, and subsequent alkylation. ...

Desilylation is also useful for the removal of silyl protecting groups. Protecting groups play an important role in organic synthesis. ...

Caesium fluoride is also a popular source of fluoride in organofluorine chemistry. For example, CsF reacts with hexafluoroacetone to form a caesium perfluoroalkoxide salt which is stable up to 60 °C, unlike the corresponding sodium or potassium salt^[6]. A fluoride ion is the ionic form of fluorine. ... link title Headline text Bold textItalic textItalic textInsert non-formatted text hereInsert non-formatted text hereInsert non-formatted text hereInsert non-formatted text hereInsert non-formatted text here--220. ... General Name, Symbol, Number sodium, Na, 11 Series alkali metal Group, Period, Block 1 (IA), 3, s Density, Hardness 968 kg/m3, 0. ... General Name, Symbol, Number potassium, K, 19 Series alkali metals Group, Period, Block 1(IA), 4, s Density, Hardness 856 kg/m3, 0. ...

Precautions

Like soluble fluorides, CsF is moderately toxic, see Elf Atochem MSDS sheet (http://www.hazard.com/msds/f2/bms/bmsqc.html). Contact with acid should be avoided, as this forms highly toxic/corrosive hydrofluoric acid. Caesium ion (Cs⁺) per se (for example as CsCl (http://www.jtbaker.com/msds/englishhtml/c1903.htm)) is not generally considered toxic. A substance is soluble in a fluid if it dissolves in the fluid. ... A fluoride ion is the ionic form of fluorine. ... An acid (often represented by the generic formula AH) is typically a water-soluble, sour-tasting chemical compound. ... Hydrofluoric acid is a highly corrosive solution of the chemical compound hydrogen fluoride in water. ... An ion is an elementary particle or system of elementary particles with a net electric charge. ...

Suppliers/Manufacturers

Fluorochem: http://www.fluorochem.co.uk/

Aldrich: http://www.sigmaaldrich.com

Strem: http://www.strem.com/code/index.ghc

Alfa: http://www.alfa.com/alf/index.htm

Synquest: http://www.synquestlabs.com/catalog/catalog.html

In the US, several of these suppliers also distribute through

Fisher: https://www1.fishersci.com/index.jsp

or VWR: http://www.vwr.com/index.htm

References

1. N. N. Greenwood, A. Earnshaw, Chemistry of the Elements, Pergamon Press, Oxford, UK, 1984.
2. Handbook of Chemistry and Physics, 71st edition, CRC Press, Ann Arbor, Michigan, 1990.
3. G. K. Friestad, B. P. Branchaud, in: Handbook of Reagents for Organic Synthesis: Acidic and Basic Reagents, (H. J. Reich, J. H. Rigby, eds.), pp99-103, Wiley, New York, 1999.
4. L. Rand, J. V. Swisher, C. J. Cronin Journal of Organic Chemistry 27, 3505 (1962).
5. M. Fiorenza, A. Mordini, S. Papaleo, S. Pastorelli, A. Ricci Tetrahedron Letters 26, 787 (1985).
6. F. W. Evans, M. H. Litt, A. M. Weidler-Kubanek, F. P. Avonda Journal of Organic Chemistry 33, 1837-1839 (1968).