Images (1)
Silica
Synonym(s)
DefinitionThis section has been translated automatically.
Silicic acids are the oxygen acids of silicon. Silicic acids form a rich group of substances that occur in nature in various compounds and formations.
The simplest silica, the monosilicic acid (orthosilicic acid), H4SiO4, is not stable. Immediately after formation, it changes into di-silicic acid by releasing water. In the further course of the process, several molecules of orthosilicic acid come together to form larger aggregates, the polysilicic acid. Polysilicic acid can combine to form long chains and ring formations (cyclic silicas).
Note(s)This section has been translated automatically.
The salts of silicic acids are called silicates (silicates). The esters of silicic acids are called silicic acid esters. A silica gel is a colloidal silica of elastic to solid consistency.
In nature, silicic acid derivatives are found in plant and animal life, e.g. in the widely distributed diatoms. The skeleton of horsetail also contains relevant amounts of polysilicic acid.
As a food additive, silica anhydride is designated E 551.
In cosmetics calcium silicates (INCI designation) play an important role as absorbents and opacifiers, as viscosity promoters and pearlescent agents.