Silicate

Silicate is a term used in chemistry to denote a compound containing an anionic silicon compound. It is the most abundant group of minerals in the Earth's crust and includes minerals like quartz, feldspar, and mica. Silicates are also present in water and the atmosphere, and are a major component of many rock types.

Structure and bonding

Silicates are based on the tetrahedral SiO4 unit, where a central silicon atom is surrounded by four oxygen atoms. This structure can form extended networks, as the oxygen atoms can bond to other silicon atoms. This leads to the formation of various structures, such as chains, sheets, and three-dimensional frameworks.

Types of silicates

Silicates can be classified into several types based on their structure:

• Nesosilicates or island silicates: These have isolated SiO4 tetrahedra that are not connected to each other. Examples include olivine and garnet.

• Sorosilicates or double island silicates: These have two SiO4 tetrahedra sharing one oxygen atom. An example is axinite.

• Cyclosilicates or ring silicates: These have rings of SiO4 tetrahedra. Examples include tourmaline and beryl.

• Inosilicates or chain silicates: These have chains of SiO4 tetrahedra. Examples include pyroxene and amphibole.

• Phyllosilicates or sheet silicates: These have sheets of SiO4 tetrahedra. Examples include mica and clay minerals.

• Tectosilicates or framework silicates: These have three-dimensional frameworks of SiO4 tetrahedra. Examples include quartz and feldspar.

Uses of silicates

Silicates are used in a wide range of applications. They are used in the manufacture of glass, ceramics, and cement. They are also used in insulation materials, abrasives, and sealants. In addition, silicates are used in agriculture as soil conditioners and in water treatment processes.

See also

• Silicon
• Mineral
• Rock (geology)

References

Silicate Resources
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