Potassium silicate is the name for a family of

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemist ...

s. The most common potassium silicate has the formula K₂SiO₃, samples of which contain varying amounts of

water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...

. These are white solids or colorless solutions.Gerard Lagaly, Werner Tufar, A. Minihan, A. Lovell "Silicates" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, 2005.

Synthesis, structure, reactions

Potassium silicate can be synthesized in the laboratory by treating silica with

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which exp ...

, according to this idealized equation: :\mathit + 2KOH -> K2O.\mathit + H2O These solutions are highly alkaline. Addition of acids causes the reformation of silica. K₂SiO₃ adopts a chain or cyclic structures with interlinked SiO₃²⁻ monomers. Each Si is tetrahedral.

Uses

Woodwork protection against fire

Impregnation of wood with a potassium silicate solution is an easy and low cost way for rendering the woodwork of houses secure against catching fire. The woodwork is first saturated with a diluted and nearly neutral solution of potash silicate. After drying, one or two coats of a more concentrated solution are usually applied.

Horticulture

horticulture Horticulture is the branch of agriculture that deals with the art, science, technology, and business of plant cultivation. It includes the cultivation of fruits, vegetables, nuts, seeds, herbs, sprouts, mushrooms, algae, flowers, seaweeds and no ...

, potassium silicate is used as a soluble source of

potassium Potassium is the chemical element with the symbol K (from Neo-Latin ''kalium'') and atomic number19. Potassium is a silvery-white metal that is soft enough to be cut with a knife with little force. Potassium metal reacts rapidly with atmosphe ...

and

silica Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...

. It makes the growing medium more alkaline. It is also used as a supplement (in conjunction with normal

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

) for the numerous benefits that increasing the availability of silicon compounds has. Silicon-containing compounds are valuable to a plant, and serve to support the plant. Stems thicken, the plant becomes more tolerant to drought and resists wilting, and the plant gets larger leaves and fruit (because the stem can support more weight). The thicker cell walls of the plant also provides an added mechanical resistance to sap sucking insects (e.g.

spider mite Spider mites are members of the Tetranychidae family, which includes about 1,200 species. They are part of the subclass Acari (mites). Spider mites generally live on the undersides of leaves of plants, where they may spin protective silk webs, a ...

) and various pathogenic fungi (e.g.

powdery mildew Powdery mildew is a fungal disease that affects a wide range of plants. Powdery mildew diseases are caused by many different species of ascomycete fungi in the order Erysiphales. Powdery mildew is one of the easier plant diseases to identify, as ...

Industrial uses

Some metal cleaning formulations use potassium silicate, which also serves as a corrosion inhibitor. It also finds various uses in the fabrication of

welding rods Plastic welding is welding for semi-finished plastic materials, and is described in ISO 472 as a process of uniting softened surfaces of materials, generally with the aid of heat (except solvent welding). Welding of thermoplastics is accomplishe ...

or even of cosmetics.

Safety

Potassium silicate is strongly alkaline.

References

External links

{{DEFAULTSORT:Potassium Silicate Inorganic silicon compounds Potassium compounds Silicates Glass compositions