The key difference between sodium silicate and sodium metasilicate is that the term sodium silicate refers to silicate salts of sodium ions whereas sodium metasilicate is a type of sodium silicate having a sodium cation and SiO32- anion.
Sodium silicate is a generic name (common name for all ionic compounds having the general chemical formula Na2xSiyO2y+x). Therefore, sodium metasilicate is a type of sodium silicate.
CONTENTS
1. Overview and Key Difference
2. What is Sodium Silicate
3. What is Sodium Metasilicate
4. Side by Side Comparison – Sodium Silicate vs Sodium Metasilicate in Tabular Form
5. Summary
What is Sodium Silicate?
Sodium silicate is a common name for all ionic compounds having the general chemical formula Na2xSiyO2y+x. The most common members of this group include sodium metasilicate, sodium orthosilicate and sodium pyrosilicate. Often, the anions in these sodium silicates are polymeric substances. Generally, sodium silicates are colorless, transparent solid compounds that are available as either solids or white powder form that is soluble in water (except for most silicon-rich silicates). When dissolved in water, sodium silicates form aqueous alkaline solutions.
Sodium silicates are stable in neutral and alkaline solutions. When they are in acidic solutions, the silicate ion tends to react with the hydrogen ions, forming silicic acid. These silicic acid components tend to decompose into hydrated silicon dioxide gel. When this hydrated compound is heated to drive off the water, it results in a hard, translucent substance that we name as silica gel (a common desiccant).
There are several methods to produce sodium silicates, depending on the type of silicate. Typically, a sodium silicate is produced by treating a mixture of silica, caustic soda, and water in the presence of hot steam. In addition, we can get a sodium silicate via dissolving silica in molten sodium carbonate.
There are many applications of sodium silicate: as ingredients in detergents, paper, water treatment, construction materials, as drilling fluid in bore walls, in metal repairing, automotive repairing, etc.
What is Sodium Metasilicate?
Sodium metasilicate is an inorganic compound having the chemical formula Na2SiO3. It is the main ingredient in commercially available sodium silicate solutions. This is an ionic compound containing sodium cations and polymeric metasilicate anions. This ionic compound is a colorless, crystalline and hygroscopic solid that is highly deliquescent. It is soluble in water but not soluble in alcohols.
Figure 01: Structure of Sodium Metasilicate
When considering the production of sodium metasilicate, we can produce it by fusing silicon dioxide with sodium oxide in 1:1 molar ratio. Moreover, sodium silicate crystallizes from various hydrate solutions such as pentahydrate and nonahydrate.
There are many important uses of sodium metasilicate including the production of silica via the reaction between sodium metasilicate and acids, production of cement and binders, pulp, paper, soap, detergent, automotive applications, egg preservative, crafts, etc.
What is the Difference Between Sodium Silicate and Sodium Metasilicate?
Sodium metasilicate is a type of sodium silicate. The key difference between sodium silicate and sodium metasilicate is that sodium silicate refers to different ionic compounds which are silicate salts of sodium ions whereas sodium metasilicate is a type of sodium silicate having a sodium cation and SiO32- anion.
Below infographic summarizes the difference between sodium silicate and sodium metasilicate.
Summary – Sodium Silicate vs Sodium Metasilicate
Sodium silicates are inorganic ionic compounds. Sodium metasilicate is a type of sodium silicate. The key difference between sodium silicate and sodium metasilicate is that the term sodium silicate refers to the different ionic compounds (silicate salts of sodium ions) whereas sodium metasilicate is a type of sodium silicate having a sodium cation and SiO32- anion.
Reference:
1. “Sodium Silicate.” Wikipedia, Wikimedia Foundation, 22 Apr. 2020, Available here.
Image Courtesy:
1. “Na2SiO3idealized” By Smokefoot – Own work (CC BY-SA 4.0) via Commons Wikimedia