Potassium fluorosilicate

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Potassium fluorosilicate
Names
Preferred IUPAC name
Potassium fluorosilicate
Other names
Potassium hexafluorosilicate(IV)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.037.163 OOjs UI icon edit-ltr-progressive.svg
EC Number
PubChem CID
RTECS number
  • VV8400000
UNII
UN number 2655
  • InChI=1S/F6Si.2K/c1-7(2,3,4,5)6;;/q-2;2*+1
    Key: UUHPPUWEDCVPCO-UHFFFAOYSA-N
  • F[Si-2](F)(F)(F)(F)F.[K+].[K+]
Properties
K2[SiF6]
Molar mass 220.28 g·mol−1 [1]
Density 2.27 g·cm−3, [1] 2.719 g·cm−3 [2]
Slightly soluble in water
Structure
cubic
Fm3m
a = 0.8134 nm
0.538.2 nm3
4
Hazards
GHS labelling:
GHS-pictogram-skull.svg
Danger
H301, H311, H331
P261, P264, P270, P271, P280, P301+P310, P302+P352, P304+P340, P311, P312, P321, P322, P330, P361, P363, P403+P233, P405, P501
Related compounds
Other cations
Ammonium hexafluorosilicate
Sodium fluorosilicate

Fluorosilicic acid

Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

Potassium fluorosilicate is a chemical compound with the chemical formula K2[SiF6].

Contents

When doped with potassium hexafluoromanganate(IV) (K2[MnF6], with Mn4+) it forms a narrow band red producing phosphor, (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 (Sicily, Italy). [3] A hexagonal form demartinite has also been found at the rim of volcanic fumaroles in the same islands. [4]

The sea sponge Halichondria Moorei builds a skeleton of potassium fluorosilicate. [5]

Structure and properties

According to analysis by Loehlin (1984), it has space group Fm3m, with a0 = 0.8134 nm, V = 0.538.2 nm3 at 295 K. The Si-F bond length is 0.1683 nm. [2] At high temperatures and pressures -beta and -gamma phases exist. [6]

Applications

Potassium fluorosilicate has applications in porcelain manufacture, the preservation of timber, aluminium and magnesium smelting, and the manufacture of optical glass. [1]

Red phosphor

When doped with potassium hexafluoromanganate(IV) (K2[MnF6]), a narrow band red phosphor is produced, emitting at around 630 nm. This substance has application improving the white light quality of white LEDs that use a blue emitting LED in combination with the yellow cerium doped yttrium aluminium garnet phosphor (YAG), Y3Al5O12:Ce3+. [7]

Synthesis routes to the phosphor include co-crystallisation and co-precipitation. For example, K2[MnF6] in (40 %) hydrofluoric acid with potassium fluoride can be mixed with SiO2 dissolved in (40 %) hydrofluoric acid to co-precipitate the phosphor. [6]

The acronyms KSF or PSF are used for potassium fluorosilicate phosphors. [8]

See also

Related Research Articles

<span class="mw-page-title-main">Terbium</span> Chemical element with atomic number 65 (Tb)

Terbium is a chemical element; it has the symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable and ductile. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. Terbium is never found in nature as a free element, but it is contained in many minerals, including cerite, gadolinite, monazite, xenotime and euxenite.

<span class="mw-page-title-main">Phosphor</span> Luminescent substance

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 or visible light, and cathodoluminescent substances which glow when struck by an electron beam in a cathode-ray tube.

<span class="mw-page-title-main">Sodium fluoride</span> Ionic compound (NaF)

Sodium fluoride (NaF) is an inorganic compound with the formula NaF. It is a colorless or white solid that is readily soluble in water. It is used in trace amounts in the fluoridation of drinking water to prevent tooth decay, and in toothpastes and topical pharmaceuticals for the same purpose. In 2022, it was the 221st most commonly prescribed medication in the United States, with more than 1 million prescriptions. It is also used in metallurgy and in medical imaging.

<span class="mw-page-title-main">Manganese(III) fluoride</span> Chemical compound

Manganese(III) fluoride (also known as Manganese trifluoride) is the inorganic compound with the formula MnF3. This red/purplish solid is useful for converting hydrocarbons into fluorocarbons, i.e., it is a fluorination agent. It forms a hydrate and many derivatives.

<span class="mw-page-title-main">Potassium fluoride</span> Ionic compound (KF)

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 salt and occurs naturally as the rare mineral carobbiite. Solutions of KF will etch glass due to the formation of soluble fluorosilicates, although HF is more effective.

<span class="mw-page-title-main">Hydrogen fluoride</span> Chemical compound

Hydrogen fluoride (fluorane) is an inorganic compound with chemical formula HF. It is a very poisonous, colorless gas or liquid that dissolves in water to yield hydrofluoric acid. It is the principal industrial source of fluorine, often in the form of hydrofluoric acid, and is an important feedstock in the preparation of many important compounds including pharmaceuticals and polymers such as polytetrafluoroethylene (PTFE). HF is also widely used in the petrochemical industry as a component of superacids. Due to strong and extensive hydrogen bonding, it boils at near room temperature, which is much higher of a temperature than other hydrogen halides.

<span class="mw-page-title-main">Plutonium tetrafluoride</span> Chemical compound

Plutonium(IV) fluoride is a chemical compound with the formula PuF4. This salt is generally a brown solid but can appear a variety of colors depending on the grain size, purity, moisture content, lighting, and presence of contaminants. Its primary use in the United States has been as an intermediary product in the production of plutonium metal for nuclear weapons usage.

<span class="mw-page-title-main">Tantalum pentoxide</span> Chemical compound

Tantalum pentoxide, also known as tantalum(V) oxide, is the inorganic compound with the formula Ta
2
O
5
. It is a white solid that is insoluble in all solvents but is attacked by strong bases and hydrofluoric acid. Ta
2
O
5
is an inert material with a high refractive index and low absorption, which makes it useful for coatings. It is also extensively used in the production of capacitors, due to its high dielectric constant.

<span class="mw-page-title-main">Hexafluorosilicic acid</span> Octahedric silicon compound

Hexafluorosilicic acid is an inorganic compound with the chemical formula H
2
SiF
6
. Aqueous solutions of hexafluorosilicic acid consist of salts of the cation and hexafluorosilicate anion. These salts and their aqueous solutions are colorless.

<span class="mw-page-title-main">Ammonium bifluoride</span> Chemical compound

Ammonium bifluoride is an inorganic compound with the formula [NH4][HF2] or [NH4]F·HF. It is produced from ammonia and hydrogen fluoride. This colourless salt is a glass-etchant and an intermediate in a once-contemplated route to hydrofluoric acid.

<span class="mw-page-title-main">Zirconium tetrafluoride</span> Chemical compound

Zirconium(IV) fluoride describes members of a family inorganic compounds with the formula ZrF4(H2O)x. All are colorless, diamagnetic solids. Anhydrous Zirconium(IV) fluoride is a component of ZBLAN fluoride glass.

<span class="mw-page-title-main">Lead(II) fluoride</span> Chemical compound

Lead(II) fluoride is the inorganic compound with the formula PbF2. It is a white solid. The compound is polymorphic, at ambient temperatures it exists in orthorhombic (PbCl2 type) form, while at high temperatures it is cubic (Fluorite type).

<span class="mw-page-title-main">Hexafluorophosphate</span> Anion with the chemical formula PF6–

Hexafluorophosphate is an anion with chemical formula of [PF6]. It is an octahedral species that imparts no color to its salts. [PF6] is isoelectronic with sulfur hexafluoride, SF6, and the hexafluorosilicate dianion, [SiF6]2−, and hexafluoroantimonate [SbF6]. In this anion, phosphorus has a valence of 5. Being poorly nucleophilic, hexafluorophosphate is classified as a non-coordinating anion.

<span class="mw-page-title-main">Fluorapatite</span> Phosphate mineral

Fluorapatite, often with the alternate spelling of fluoroapatite, is a phosphate mineral with the formula Ca5(PO4)3F (calcium fluorophosphate). Fluorapatite is a hard crystalline solid. Although samples can have various color (green, brown, blue, yellow, violet, or colorless), the pure mineral is colorless, as expected for a material lacking transition metals. Along with hydroxylapatite, it can be a component of tooth enamel, especially in individuals who use fluoridated toothpaste, but for industrial use both minerals are mined in the form of phosphate rock, whose usual mineral composition is primarily fluorapatite but often with significant amounts of the other.

<span class="mw-page-title-main">Manganese(IV) fluoride</span> Chemical compound

Manganese tetrafluoride, MnF4, is the highest fluoride of manganese. It is a powerful oxidizing agent and is used as a means of purifying elemental fluorine.

<span class="mw-page-title-main">Bismuth trifluoride</span> Chemical compound

Bismuth(III) fluoride or bismuth trifluoride is a chemical compound of bismuth and fluorine. The chemical formula is BiF3. It is a grey-white powder melting at 649 °C.

<span class="mw-page-title-main">Bararite</span> Halide mineral

Bararite is a natural form of ammonium fluorosilicate (also known as hexafluorosilicate or fluosilicate). It has chemical formula (NH4)2SiF6 and trigonal crystal structure. This mineral was once classified as part of cryptohalite. Bararite is named after the place where it was first described, Barari in Jharia Coal Field, Dhanbad, India. It is found at the fumaroles of volcanoes (Vesuvius, Italy), over burning coal seams (Barari, India), and in burning piles of anthracite (Pennsylvania, U.S.). It is a sublimation product that forms with cryptohalite, sal ammoniac, and native sulfur.

Fluorine forms a great variety of chemical compounds, within which it always adopts an oxidation state of −1. With other atoms, fluorine forms either polar covalent bonds or ionic bonds. Most frequently, covalent bonds involving fluorine atoms are single bonds, although at least two examples of a higher order bond exist. Fluoride may act as a bridging ligand between two metals in some complex molecules. Molecules containing fluorine may also exhibit hydrogen bonding. Fluorine's chemistry includes inorganic compounds formed with hydrogen, metals, nonmetals, and even noble gases; as well as a diverse set of organic compounds. For many elements the highest known oxidation state can be achieved in a fluoride. For some elements this is achieved exclusively in a fluoride, for others exclusively in an oxide; and for still others the highest oxidation states of oxides and fluorides are always equal.

<span class="mw-page-title-main">Fluorocarbonate</span> Class of chemical compounds

A carbonate fluoride, fluoride carbonate, fluorocarbonate or fluocarbonate is a double salt containing both carbonate and fluoride. The salts are usually insoluble in water, and can have more than one kind of metal cation to make more complex compounds. Rare-earth fluorocarbonates are particularly important as ore minerals for the light rare-earth elements lanthanum, cerium and neodymium. Bastnäsite is the most important source of these elements. Other artificial compounds are under investigation as non-linear optical materials and for transparency in the ultraviolet, with effects over a dozen times greater than Potassium dideuterium phosphate.

<span class="mw-page-title-main">Pertechnetyl fluoride</span> Chemical compound

Pertechnetyl fluoride is an inorganic compound, a salt of technetium and hydrofluoric acid with the chemical formula TcO
3
F
. The compound was originally synthesized by H. Selig and G. Malm in 1963.

References

  1. 1 2 3 4 "44495 Potassium hexafluorosilicate, 99.999 % (metals basis)", www.alfa.com
  2. 1 2 Loehlin, J. H. (1984), "Redetermination of the structure of potassium hexafluorosilicate, K2SiF6", Acta Crystallographica, C40 (3): 570, Bibcode:1984AcCrC..40..570L, doi:10.1107/S0108270184004893
  3. "Hieratit", www.mineralienatlas.de
  4. Gramaccioliss, Carlo Maria; Campostrini, Italo (2007), "Demartinite, a new polymorph of K2SiF6 from la Fossa Crater, Vulcano, Aeolian Islands, Italy", The Canadian Mineralogist, 45 (5): 1275–1280, Bibcode:2007CaMin..45.1275G, doi:10.2113/gscanmin.45.5.1275
  5. Gregson (30 Nov 1979), "Fluorine is a major constituent of the marine sponge Halochondria Moorei", Science, 206 (4422): 1108–1109, doi:10.1126/science.206.4422.1108 {{citation}}: CS1 maint: date and year (link)
  6. 1 2 Verstraete, Reinert; Sijbom, Heleen F.; Joos, Jonas J.; Korthout, Katleen; Poelman, Dirk; Detavernier, Christophe; Smet, Philippe F. (2018), "Red Mn4+-Doped Fluoride Phosphors: Why Purity Matters" (PDF), ACS Applied Materials & Interfaces, 10 (22): 18845–18856, doi: 10.1021/acsami.8b01269 , PMID   29750494
  7. Sijbom, Heleen F.; Verstraete, Reinert; Joos, Jonas J.; Poelman, Dirk; Smet, Philippe F. (1 Sep 2017), "K2SiF6:Mn4+ as a red phosphor for displays and warm-white LEDs: a review of properties and perspectives", Optical Materials Express, 7 (9): 3332, Bibcode:2017OMExp...7.3332S, doi: 10.1364/OME.7.003332
  8. Happich, Julien (20 Nov 2017), "Differentiate or loose! Yole's analysis on LED phosphors and QDs", www.eenewseurope.com