What is silicon dioxide used for?

Silicon dioxideSilicon dioxide is the oxide of silicon. It is a natural substance that occurs in crystalline form, for example in quartz, granite and sand, and is used for the manufacture of glass. Various grades of silicon dioxide are widely used as excipients in pharmacy. Among other things, silicon dioxide is used as a flow regulator, to control viscosity, as an adsorbent, gel former, disintegrant, antistatic agent and as a stabilizer. When working with powdered silicon dioxide, respiratory protection should be worn to avoid inhalation.

Synonymous: Silica, Silca colloidalis, SiO2, Silicon dioxide, Aerosil®, quartz


Pure silicon dioxide in pharmacopoeia quality is available in pharmacies and drug stores.

Note: In English, silicon meansSilicone and silicon dioxide is referred to as silicon dioxide.

Structure and properties

Silicon dioxide (SiO2, Mr = 60.08 g / mol) is the oxide of silicon. It is available, for example, as a fine, white powder and is practically insoluble in water and in most mineral acids. This is with the exception of hydrofluoric acid (HF). It is also soluble in hot caustic soda. Silica has a high melting point of 1710 ° C.

The pharmacopoeia distinguishes between different qualities:

The various products differ, for example, in their behavior towards water (hydrophilic, hydrophobic), in the grain size (powder, granulate), the pH value, in the surface area and in the density.

Silicon dioxide occurs very frequently in nature, for example in sand and quartz (e.g. rock crystal). Quartz is also a component of granite. Silica is the most important component of glass. It is also found in living things, for example in diatoms.

In the crystal, silicon dioxide is typically in a network with a tetrahedral arrangement, where each oxygen atom is shared by two silicon atoms:


In pharmacy, silicon dioxide is used in a wide variety of ways, including as a flow regulator, carrier, viscosity control, adsorbent, gelling agent (oleogels), disintegrant, antistatic, thixotropic agent, anti-clumping and stabilizer.

Areas of application Unwanted effects

When working with powdered silicon dioxide, respiratory protection should be worn to prevent inhalation, which, among other things, can lead to pneumonia and pneumonia.

see also

Silicon, oxygen

  • Medicinal product information (CH)
  • European Pharmacopoeia PhEur
  • Specialist literature
  • Manufacturer information
  • Pharmaceutical Technology Textbooks

Conflicts of Interest: None / Independent. The author has no relationships with the manufacturers and is not involved in the sale of the products mentioned.

additional Information
Support PharmaWiki with a donation!

© PharmaWiki 2007-2021 - PharmaWiki provides independent and reliable information about medication and health.
This article was last changed on December 9, 2019.
Imprint and data protection declaration
Show products for this page