Silicon dioxide, commonly known as silica, is a chemical compound composed of silicon and oxygen. The formation of SiO2 can be represented by the following oxidation-reduction (redox) reaction:

Si0 - 8 e- → SiVIII (oxidation)

4 O0 + 8 e- → 4 O-II (reduction)

In this reaction, silicon is being oxidized while oxygen is being reduced. This means that silicon acts as a reducing agent, while oxygen acts as an oxidizing agent.

The chemical equation for the formation of SiO2 is:

Si + O2 → SiO2

This equation represents the combination of silicon and oxygen atoms to form silicon dioxide. The stoichiometric coefficients for this reaction are not included because the reaction occurs at the molecular level.

Silicon dioxide is an important compound with various industrial applications, including as a raw material for glass production, as a filler for rubber and plastics, and as an abrasive for cutting and polishing. In the natural world, silica is a major component of many minerals and rocks, including quartz, opal, and sandstone.

The orthosilicate anion is a common form of silicon dioxide in which four oxygen atoms surround a single silicon atom, forming a tetrahedral structure. The chemical formula for the orthosilicate anion is SiO4:4-.