Fluorisilikaatteja

Fluorisilikaatteja, known in English as fluorosilicates or fluosilicate salts, are a group of inorganic compounds with the general formula M₂SiF₆, where M is a univalent cation like sodium (Na⁺), potassium (K⁺), or ammonium (NH₄⁺). They can also be represented as MSiF₆ if M is a divalent cation such as magnesium (Mg²⁺) or calcium (Ca²⁺). These compounds are salts derived from hydrofluorosilicic acid (H₂SiF₆). Fluorisilikaatteja are typically crystalline solids that are often soluble in water, though their solubility varies depending on the specific cation.

Industrially, fluorosilicates are often produced as byproducts of phosphate fertilizer manufacturing. During the processing of phosphate rock, which contains fluoride minerals, hydrofluoric acid is released. This acid reacts with silica to form hydrofluorosilicic acid, which can then be neutralized with various bases to produce different fluorosilicate salts. For example, sodium fluorosilicate (Na₂SiF₆) is formed by reacting hydrofluorosilicic acid with sodium chloride or sodium hydroxide.

Fluorisilikaatteja have several practical applications. Sodium fluorosilicate, for instance, is commonly used as a fluoridating agent in municipal water supplies to help prevent tooth decay. It is also employed as an insecticide, particularly against cockroaches and ants, and as a mothproofing agent for wool. Other fluorosilicates find uses in various industries, including metallurgy for refining aluminum and as fluxes in welding. However, they are also toxic, and precautions are necessary when handling them.