Overview

Silicon dioxide (SILL-uh-kon dye-OK-side) is one of the most abundant chemical compounds on Earth. It makes up about 60 percent of the weight of the Earth's crust either as an independent compound (SiO₂) or in combination with metallic oxides that form silicates. Silicates are inorganic compounds whose negative part is the SiO₃⁻ ion (grouping of atoms). An example is magnesium silicate, MgSiO₃.

Key Facts

Other Names:

Silica, quartz, sand, amorphous silica, silica gel, and others

Formula:

SiO₂

Elements:

Silicon, oxygen

Compound Type:

Nonmetallic oxide (inorganic)

State:

Solid

Molecular Weight:

60.08 g/mol

Melting Point:

Varies depending on crystalline state; typically above 1700°C (3100°F)

Boiling Point:

2950°C (5300°F)

Solubility:

Solubility depends on crystalline state; generally insoluble in water; soluble in many acids and alkalis

Silicon dioxide occurs as colorless, odorless, tasteless white or colorless crystals or powder. Its many different forms can be classified as crystalline, amorphous, or...