What is the Difference Between Sodium Silicate and Sodium Metasilicate?

Sodium silicate and sodium metasilicate are inorganic sodium salts with silicate as the counterion. Both compounds have the chemical formula (Na2O)x·SiO2, but they differ in their ratios of sodium oxide (Na2O) to silicon dioxide (SiO2). The key difference between the two is:

Sodium Silicate: This term refers to a mixture of various compounds with the formula Na2xSi yO 2y+x or (Na2O)x·(SiO2)y, including sodium metasilicate, sodium orthosilicate (Na4SiO4), and sodium pyrosilicate (Na6Si2O7). Sodium silicate is used in a wide variety of applications, such as cements, coatings, passive fire protection, textile and lumber processing, refractory ceramics, adhesives, and silica gel production.
Sodium Metasilicate: This is a specific type of sodium silicate with the formula Na2SiO3, also known as waterglass or liquid glass. It is a colorless, crystalline, and hygroscopic solid that is highly deliquescent and soluble in water but not in alcohols. Sodium metasilicate is used in various applications, including the production of silica via cement and binders, pulp, paper, soap, detergents, rust removers, grinding aids for ceramics, deinking agents for paper, and dyeing and printing auxiliaries for removing oil in the textile industry.

Both compounds are stable in neutral and alkaline solutions, but in acidic solutions, the silicate ions react with hydrogen ions to form silicic acid, which, when heated and roasted, forms silica gel, a hard, glassy substance.

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What is the Difference Between Sodium Silicate and Sodium Metasilicate?

Comparative Table: Sodium Silicate vs Sodium Metasilicate

Sodium silicate and sodium metasilicate are both inorganic compounds, but they differ in their chemical formulas, properties, and applications. Here is a table comparing the two:

Property	Sodium Silicate	Sodium Metasilicate
Chemical Formula	Na₂SiO₃	Na₂SiO₃
Properties	Ionic compound, colorless, crystalline, hygroscopic, highly deliquescent, soluble in water but not in alcohols	Ionic compound containing sodium cations and polymeric metasilicate anions
Production	Obtained by dissolving silica in molten sodium carbonate	Produced by fusing silicon dioxide with sodium oxide in a 1:1 molar ratio
Applications	Ingredient in detergents, paper, water treatment, construction materials, drilling fluid in bore walls, and automotive repairing	Main ingredient in commercially available sodium silicate solutions, used in detergent and automotive applications

Sodium silicate is a raw material for sodium metasilicate, and sodium metasilicate is a type of sodium silicate. While they share some similarities, such as being ionic compounds and having a sodium-silicate-based structure, they differ in their chemical formulas, properties, and specific applications.

Guilherme Mazui

Guilherme Mazui is graduated in journalism from the Federal University of Minas Gerais (UFMG) and a master's degree in Communication from the University of São Paulo (USP). In addition, he has experience in advertising writing and has worked as a content editor in several companies.