Potassium fluorosilicate

Potassium fluorosilicate [16871-90-2] M 220.3, d 2.3, pK 1.92 (for H2SiFconductivity water (lOOmL/g) between 100° and 0°. 

The most effective of the proposed solutions seem to be solutions of ammonium carbonate, (NH4)2C03. Such solutions were also recommended by Mulyarchuk and Panchenko [500] for the decomposition of potassium fluorosilicate, K2SiF6. 

Jons Jakob Berzelius (1779-1848) treated potassium fluorosilicate with potassium to obtain amorphous silicon as a brown powder. 

Earlier corrosion inhibitors limited the maximum strength of the acid to 15% by weight. Improved corrosion inhibitors (see below) have made the use of higher acid concentrations, such as 28% HCl more common. More dilute solutions may initially be injected in sandstone acidizing to reduce the formation of insoluble sodium and potassium fluorosilicates by displacing saline formation water before injection of hydrochloric acid. 

The first marginally successful synthesis of elemental silicon was carried out in 1811 by Joseph Louis Gay-Lussac and Louis J. Thenard, who passed silicon fluoride over heated potassium. However, a much more successful method was used by Swedish chemist Jons Jacob Berzelius in 1824, which involved the reduction of potassium fluorosilicate with metallic potassium. The element silicon was eventually recognized to he one of the most abundant in the lithosphere, that is, the crust of the Earth. Remarkably, even at that early stage, a debate developed as to whether silicon was a metal or an insulator, with Berzelius taking the view that... 

See Magnesium myreth sulfate Magnesium POE (1-4) oleyl ether sulfate. See Magnesium oleth sulfate Magnesium potassium fluorosilicate Synonyms Silicate (2-), hexafluoro, magnesium potassium salt Classification Inorganic salt... 

Synonyms Potassium fluorosilicate (INCI) Potassium hexafluorosilicate Potassium silicofluoride Silicate, hexafluoro-, dipotassium... 

Another method proposed by J. Berzelius—calcination of potassium fluorosilicate with an excess of potassium—proved to be more successful and straightforward. The sintered mass was decomposed with water and, as a result, pure amorphous silicon was obtained. J. Berzelius showed that upon calcination silicon was transformed into silica this makes Berzelius the discoverer of silicon. Crystalline silicon was obtained in 1854 by A. Saint Claire Deville during separation of metallic aluminium (see p. 109). The Latin name silicium originates from silex meaning a hard stone . 

Without doubt one of the key events of silicon science occurred in 1824 when Berzelius [12] first Isolated silicon by the reduction of potassium fluorosilicate, K.SIF, with potassium metal and then showed that this element reacted with chlorine to give a volatile, highly reactive material subsequently identified as silicon tetrachloride, SiCl. The next step from silicon to organosilicon science was accomplished by Friedle and Craft [13] in 1865 when they obtained tetraethylsilane by reaction of silicon tetrachloride with dlethylzinc ... 

Sodium fluorosilicate Na2SiF6 and potassium fluorosilicate K2SiFg are poorly water soluble (in cold water about 0.6% for the sodium salt, and only 0.12% for the potassium salt). Their solutions provoke superficial pitting corrosion. In saturated solutions, and at a temperature close to the boiling point, a black protective film that adheres well to the surface is formed. 

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