What is the Difference Between Sodium Silicate and Sodium Metasilicate

Sodium silicate and sodium metasilicate are two distinct chemical compounds with unique properties and applications. While both are alkaline substances, their molecular structures and uses differ. Understanding the difference between sodium silicate and sodium metasilicate is important for selecting the appropriate compound for specific industrial or household needs.

What is the difference between sodium silicate and sodium metasilicate? Sodium silicate is a generic term for a range of compounds containing sodium, oxygen, and silicon, whereas sodium metasilicate specifically refers to the sodium salt of metasilicic acid.

Key Areas Covered

1. What is Sodium Silicate 
      – Definition, Features, Use
2. What is Sodium Metasilicate
      – Definition, Features, Use 
3. Similarities Between Sodium Silicate and Sodium Metasilicate
      – Outline of Common Features
4. Difference Between Sodium Silicate and Sodium Metasilicate
      – Comparison of Key Differences
5. FAQ: Sodium Silicate and Sodium Metasilicate
      – Answers to Frequently Asked Questions

Key Terms

Sodium Silicate, Sodium Metasilicate

Difference Between Sodium Silicate and Sodium Metasilicate - Comparison Summary

What is Sodium Silicate

Sodium silicate, commonly known as water glass, is a chemical compound with widespread industrial applications. Composed of sodium oxide and silica, it appears as a colorless, viscous liquid or as solid, transparent beads when dehydrated. This compound is produced by fusing sodium carbonate (soda ash) and silica sand at high temperatures.

One of sodium silicate’s major properties is its ability to form a glass-like substance when exposed to air or added to water, hence the name “water glass.” This glassy material finds application in various industries, particularly in the manufacturing of detergents, adhesives, and cement. In detergents, sodium silicate acts as a corrosion inhibitor and a builder, enhancing cleaning efficiency. It’s also a key ingredient in adhesives, providing strength and stability in bonding.

In construction, sodium silicate is employed as a sealant and binder in the production of refractory materials and fire-resistant coatings. Its fire-resistant properties make it an essential component in passive fire protection.

Furthermore, sodium silicate plays a crucial role in the automotive sector, serving as a coolant in certain types of vehicle batteries. The compound’s alkaline nature contributes to stabilizing pH levels in the electrolyte, improving the battery’s performance and longevity.

While sodium silicate is an indispensable industrial chemical, its applications extend beyond manufacturing. Some experimental applications include soil stabilization and the creation of artistic effects in photography.

What is Sodium Metasilicate

Sodium metasilicate is an inorganic compound with the chemical formula Na2SiO3. Having sodium oxide and silica, it exists in various hydrated forms. Widely used in industrial and household applications, this compound exhibits excellent cleaning and detergent properties. Its alkaline nature makes it effective in breaking down oils, grease, and dirt, making it a key ingredient in many cleaning products.

Sodium Metasilicate

As a builder or sequestrant, sodium metasilicate enhances the performance of detergents by preventing the re-deposition of soil onto surfaces during cleaning. This property makes it a crucial component in laundry detergents and dishwasher powders. Furthermore, its compatibility with chlorine bleach reinforces its role in stain removal and disinfection.

Beyond its cleaning applications, sodium metasilicate finds use in industries such as textiles, ceramics, and metallurgy. In textiles, it aids in dyeing processes, while in ceramics, it acts as a binder for casting molds. Its role in metallurgy involves metal cleaning and surface treatment.

Despite its utility, the compound requires careful handling due to its alkalinity. Direct contact with skin or eyes can cause irritation, emphasizing the importance of appropriate safety measures during its use.

Similarities Between Sodium Silicate and Sodium Metasilicate

  1. Both contain sodium and silicate ions.
  2. They both have the ability to form alkaline solutions when dissolved in water.

Difference Between Sodium Silicate and Sodium Metasilicate


  • Sodium silicate is a compound with a general formula of Na2O·nSiO2, where “n” represents the molar ratio of SiO2 to Na2. Sodium metasilicate, on the other hand, has the chemical formula Na2SiO3 and is derived from sodium silicate through various processes.


  • Sodium silicate has a variable structure, with the ratio of SiO2 to Na2O affecting its properties. It is often amorphous, resembling glass. Sodium metasilicate has a more defined structure, consisting of metasilicate anions (SiO32-) and sodium cations.


  • Moreover, sodium metasilicate is also soluble in water but has a different solubility profile compared to sodium silicate.


  • Sodium silicate (water glass) is used in detergents, adhesives, concrete, fireproofing, and water treatment, while sodium metasilicate is used as a cleaning agent in household and industrial cleaners, metal surface treatment, concrete additives, and textile processing.


In conclusion, sodium silicate and sodium metasilicate are distinct compounds with diverse applications. Sodium silicate, commonly known as water glass, exhibits versatility in industries such as detergents, adhesives, and construction materials. Its glassy nature and fire-resistant properties contribute to its widespread use. On the other hand, sodium metasilicate excels in cleaning applications, serving as a key component in detergents and household cleaners due to its alkaline properties. Thus, the main difference between sodium silicate and sodium metasilicate is that while both compounds share sodium and silicate ions, their structures, solubility profiles, and applications differ, showcasing their unique roles in various industrial processes and everyday products.

FAQ: Sodium Silicate and Sodium Metasilicate

 1. What is sodium silicate used for?

Sodium silicates are used in industry as adhesives, detergents, ingredients in cleaning compounds, cement, binders, and unique coatings, as well as coagulant aids and anticorrosives.

2. Why is sodium silicate used in detergent?

In detergents and soaps, sodium silicate optimizes washing performance by controlling viscosity. Its solutions can easily be added to the detergent paste, facilitating the desired density and ensuring effective cleaning.

3. Does sodium metasilicate dissolve in water?

Yes, sodium metasilicate readily dissolves in water, forming an alkaline solution due to its hydrolysis. This dissolution process involves the breakdown of sodium metasilicate into sodium ions and silicate ions, which then interact with water molecules to produce hydroxide ions, resulting in an alkaline solution.

4. What is the pH of sodium silicate?

The pH of sodium silicate solutions typically ranges from approximately 10 to 13, making them alkaline. This alkalinity is a result of the hydrolysis of sodium silicate in water, which produces hydroxide ions.

5. What is the hardener for sodium silicate?

CO2 gas and liquid ester hardeners are the most widely used of the silicate processes. These hardeners facilitate the solidification or curing of sodium silicate, contributing to its varied applications across industries.


1. “Sodium Metasilicate.” Wikipedia. Wikipedia Foundation.
2. “Sodium Silicate.” PubChem. National Library of Medicine.

Image Courtesy:

1. “Na2SiO3idealized” By Smokefoot – Own work (CC BY-SA 4.0) via Commons Wikimedia

About the Author: Hasini A

Hasini is a graduate of Applied Science with a strong background in forestry, environmental science, chemistry, and management science. She is an amateur photographer with a keen interest in exploring the wonders of nature and science.

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