Potassium fluorosilicate


Potassium fluorosilicate is a chemical compound with the chemical formula K2.
When doped with Potassium hexfluoromangante it forms a narrow band red producing phosphor,, of economic interest due to its applicability in LED lighting and displays.

Natural occurrence

Occurs naturally as Hiereatite, found in the Aeolian islands. 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 it has space group Fmm, with a0 = 0.8134 nm, V = 0.538.2 nm3 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 including : porcelain manufacture; preservation of timber; aluminium and magnesium production ; intermediate in the manufacture of optical glass.

Red phosphor

When doped with potassium hexfluoromangante, 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 phoshor, Y3Al5O12:Ce3+.
Synthesis routes to the phoshpor include co-crystallisation and co-precipitation. For example, K2MnF6 in [hydrofluoric acid with potassium fluoride can be mixed with SiO2 dissolved in hydrofluoric acid to co-precipitate the phosphor.
The acronyms KSF or PSF are used for Potassium fluorosilicate phoshpors.