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| Names | |
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| IUPAC name Potassium fluoride | |
| Identifiers | |
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3D model (JSmol) | |
| ChEMBL | |
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| ECHA InfoCard | 100.029.228 |
| EC Number |
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| RTECS number |
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| Properties | |
| KF | |
| Molar mass | 58.0967 g/mol (anhydrous) 94.1273 g/mol (dihydrate) |
| Appearance | colourless |
| Density | 2.48 g/cm3 |
| Melting point | 858 °C (1,576 °F; 1,131 K) (anhydrous) 41 °C (dihydrate) 19.3 °C (trihydrate) |
| Boiling point | 1,502 °C (2,736 °F; 1,775 K) |
| anhydrous: 92 g/100 mL (18 °C) 102 g/100 mL (25 °C) dihydrate: 349.3 g/100 mL (18 °C) | |
| Solubility | soluble inHF insoluble inalcohol |
| −23.6·10−6 cm3/mol | |
| Structure | |
| cubic | |
| Hazards | |
| GHS labelling: | |
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| Danger | |
| H301,H311,H331[1] | |
| P261,P264,P270,P271,P280,P301+P310,P302+P352,P304+P340,P311,P312,P321,P322,P330,P361,P363,P403+P233,P405,P501 | |
| NFPA 704 (fire diamond) | |
| Flash point | Non-flammable |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 245 mg/kg (oral, rat)[2] |
| Related compounds | |
Otheranions | Potassium chloride Potassium bromide Potassium iodide |
Othercations | Lithium fluoride Sodium fluoride Rubidium fluoride Caesium fluoride Francium fluoride |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Potassium fluoride is thechemical compound with the formulaKF. Afterhydrogen fluoride, KF is the primary source of thefluoride ion for applications in manufacturing and in chemistry. It is analkali halide salt and occurs naturally as the raremineralcarobbiite. Solutions of KF will etch glass due to the formation of soluble fluorosilicates, althoughHF is more effective.
Potassium fluoride is prepared by reactingpotassium carbonate withhydrofluoric acid. Evaporation of the solution forms crystals ofpotassium bifluoride. The bifluoride on heating yields potassium fluoride:
Platinum or heat resistant plastic containers are often used for these operations.
Potassium chloride converts to KF upon treatment with hydrogen fluoride. In this way, potassium fluoride is recyclable.[3]
KF crystallizes in the cubicNaClcrystal structure. The lattice parameter at room temperature is 0.266 nm.[4]
Inorganic chemistry, KF can be used for the conversion ofchlorocarbons intofluorocarbons, via theFinkelstein (alkyl halides)[5] andHalex reactions (aryl chlorides).[3] Such reactions usually employ polar solvents such asdimethyl formamide,ethylene glycol, anddimethyl sulfoxide.[6] More efficient fluorination of aliphatic halides can be achieved with a combination ofcrown ether and bulky diols inacetonitrile solvent.[7]
Potassium fluoride on alumina (KF/Al2O3) is a base used in organic synthesis. It was originally introduced in 1979 by Andoet al. for inducing alkylation reactions.[8]
Like other sources of the fluoride ion, F−, KF is poisonous, although lethal doses approach gram levels for humans. It is harmful by inhalation and ingestion. It is highly corrosive, and skin contact may cause severe burns.
