Silica

Silica or silicon dioxide (SiO2) is a chemical compound that is an oxide of silicon with the chemical formula SiO2. It has been known since ancient times. Silica is most commonly found in nature as quartz, as well as in various living organisms. In many parts of the world, silica is the major constituent of sand.

Chemical Structure

Silica is one of the most complex and most abundant families of materials, existing as a compound of several minerals and as synthetic product. It's a three dimensional network of tetrahedra where each oxygen is shared between two tetrahedra, giving an overall formula SiO2.

Occurrence

Silica is found in nature in several forms, including quartz and opal. In fact, it has 17 crystalline forms. The most common constituent of sand in inland continental settings and non-tropical coastal settings is silica, usually in the form of quartz.

Uses

Silica is used primarily in the production of glass for windows, drinking glasses, beverage bottles, and many other uses. The majority of optical fibers for telecommunications are also made from silica. It is a primary raw material for many ceramics such as earthenware, stoneware, and porcelain.

Health Effects

Inhaling finely divided crystalline silica dust in very small quantities (OSHA PEL is 50 µg/m³) over time can lead to silicosis, bronchitis, or cancer, as the dust becomes lodged in the lungs and continuously irritates them, reducing lung capacities.

See Also

• Quartz
• Silicosis
• Silicon
• Glass
• Ceramics

Silica Resources
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