Potassium fluorosilicate
| Names | |
|---|---|
| Preferred IUPAC name
Potassium fluorosilicate | |
| Other names
Potassium hexafluorosilicate(IV)
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| Identifiers | |
3D model (JSmol)
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| ChemSpider | |
| ECHA InfoCard | 100.037.163 |
| EC Number |
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PubChem CID
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| RTECS number |
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| UNII | |
| UN number | 2655 |
CompTox Dashboard (EPA)
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| 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
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Lattice volume (V)
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0.538.2 nm3 |
Formula units (Z)
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4 |
| Hazards | |
| GHS labelling: | |
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| 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
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Ammonium hexafluorosilicate Sodium fluorosilicate |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Potassium fluorosilicate is a chemical compound with the chemical formula K2[SiF6].
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
[edit]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]
Structure and properties
[edit]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.[5]
Applications
[edit]Potassium fluorosilicate has applications in porcelain manufacture, the preservation of timber, aluminium and magnesium smelting, and the manufacture of optical glass.[1]
Red phosphor
[edit]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+.[6]
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.[5]
The acronyms KSF or PSF are used for potassium fluorosilicate phosphors.[7]
See also
[edit]References
[edit]- ^ a b c d "44495 Potassium hexafluorosilicate, 99.999 % (metals basis)", www.alfa.com
- ^ a b 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
- ^ "Hieratit", www.mineralienatlas.de
- ^ 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
- ^ a b 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
- ^ 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
- ^ Happich, Julien (20 Nov 2017), "Differentiate or loose! Yole's analysis on LED phosphors and QDs", www.eenewseurope.com