Potassium fluorosilicate is a chemical compound with the chemical formula .
When doped with Potassium hexafluoromanganate(IV) () it forms a narrow band red producing
phosphor
A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet o ...
, (often abbreviated PSF or KSF), of economic interest due to its applicability in LED lighting and displays.
Natural occurrence
Occurs naturally as
Hiereatite, found in the
Aeolian islands
The Aeolian Islands ( ; it, Isole Eolie ; scn, Ìsuli Eoli), sometimes referred to as the Lipari Islands or Lipari group ( , ) after their largest island, are a volcanic archipelago in the Tyrrhenian Sea north of Sicily, said to be named afte ...
(Sicily/Italy). A hexagonal form
Demartinite has also been found at the rim of volcanic fumaroles in the same islands.
Structure and properties
According to analysis by (Loehlin, 1984) it has space group Fmm, with a
0 = 0.8134 nm, V = 0.538.2 nm
3 at 295K. The Si-F bond length is 0.1683 nm.
[ At high temperatures and pressures -beta and -gamma phases exist.][
]
Application
Potassium fluorosilicate has applications in porcelain manufacture, the preservation of timber, aluminium and magnesium smelting, and the manufacture of optical glass.
Red phosphor
When doped with potassium hexafluoromanganate(IV) ), a narrow band red phosphor is produced, emitting at around 630 nm. This substance has application improving the white light quality of white LED
White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...
s that use a blue emitting LED in combination with the yellow cerium
Cerium is a chemical element with the symbol Ce and atomic number 58. Cerium is a soft, ductile, and silvery-white metal that tarnishes when exposed to air. Cerium is the second element in the lanthanide series, and while it often shows the +3 o ...
doped yttrium aluminium garnet phosphor (YAG), .[
Synthesis routes to the phosphor include co-crystallisation and co-precipitation. For example, in (40%) ]hydrofluoric acid
Hydrofluoric acid is a solution of hydrogen fluoride (HF) in water. Solutions of HF are colourless, acidic and highly corrosive. It is used to make most fluorine-containing compounds; examples include the commonly used pharmaceutical antidepr ...
with potassium fluoride
Potassium fluoride is the chemical compound with the formula KF. After hydrogen fluoride, KF is the primary source of the fluoride ion for applications in manufacturing and in chemistry. It is an alkali halide and occurs naturally as the rar ...
can be mixed with dissolved in (40%) hydrofluoric acid to co-precipitate the phosphor.[
The acronyms KSF or PSF are used for potassium fluorosilicate phosphors.]
See also
* Fluorosilicic acid
Hexafluorosilicic acid is an inorganic compound with the chemical formula . Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.
Hexafluo ...
* Ammonium fluorosilicate
* Sodium fluorosilicate
References
{{silicon compounds
Potassium compounds
Hexafluorosilicates
Phosphors and scintillators