Potassium fluoride is the
chemical compoundA chemical compound is a pure chemical substance consisting of two or more different chemical elements that can be separated into simpler substances by chemical reactions. Chemical compounds have a unique and defined chemical structure; they consist of a fixed ratio of atoms that are held together...
with the formula KF. After
hydrogen fluorideHydrogen fluoride is a chemical compound with the formula HF. It is the principal industrial source of fluorine, often in the aqueous form as hydrofluoric acid, and thus is the precursor to many important compounds including pharmaceuticals and polymers . HF is widely used in the petrochemical...
, KF is the primary source of the
fluorideFluoride is the anion F
−, the reduced form of fluorine. Both organic and inorganic compounds containing the element fluorine are sometimes called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are distinct relative to other...
ion for applications in manufacturing and in chemistry. It is an
alkali metalThe alkali metals are a series of chemical elements forming Group 1 of the periodic table: lithium , sodium , potassium , rubidium , caesium , and francium ....
halideA halide is a binary compound, of which one part is a halogen atom and the other part is an element or radical that is less electronegative than the halogen, to make a fluoride, chloride, bromide, iodide, or astatide compound. Many salts are halides...
and occurs naturally as the rare
mineralA mineral is a naturally occurring solid formed through geological processes that has a characteristic chemical composition, a highly ordered atomic structure, and specific physical properties. A rock, by comparison, is an aggregate of minerals and/or mineraloids, and need not have a specific...
carobbiiteCarobbiite, chemical formula KF , is a rare, soft , colorless cubic mineral. It is found at Monte Somma, Somma-Vesuvius Complex, Province of Naples, Campania, Italy. It was discovered in 1956 by Italian geologist Guido Carobbi . It has also been reported from Hokkaidō, Japan....
. Aqueous solutions of KF will etch glass due to the formation of soluble fluorosilicates, although
HFHydrofluoric acid is a solution of hydrogen fluoride in water. While it is extremely corrosive and difficult to handle, it is technically a weak acid...
is more effective.
Applications in organic chemistry
In
organic chemistryOrganic chemistry is a discipline within chemistry which involves the scientific study of the structure, properties, composition, reactions, and preparation of chemical compounds that contain carbon...
, KF is the preferred source of fluoride for the conversion of chlorocarbons into
fluorocarbonFluorocarbons, sometimes referred to as perfluorocarbons, are organofluorine compounds that contain only carbon and fluorine bonded together in strong carbon–fluorine bonds. Fluoroalkanes, that contain only single bonds, are more chemically and thermally stable than alkanes...
s. Such reactions usually employ polar solvents such as dimethyl formamide,
ethylene glycolEthylene glycol is an organic compound widely used as an automotive antifreeze and a precursor to polymers. In its pure form, it is an odorless, colorless, syrupy, sweet tasting liquid....
, and
dimethyl sulfoxideDimethyl sulfoxide is the chemical compound with the formula
2SO. It was first synthesized in 1866 by the Russian scientist Alexander Zaytsev, who reported his findings in a German chemistry journal in 1867...
.
Safety considerations
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, highly corrosive and skin contact may cause severe burns.