Silicat

Silicat is a term used for chemical compounds and minerals that contain silicon and oxygen, typically with one or more metal cations. In geology and mineralogy, silicates represent the largest and most varied class of minerals, forming the bulk of Earth's crust and many igneous, metamorphic, and sedimentary rocks.

The essential structural unit of silicates is the silicon-oxygen tetrahedron, [SiO4]4−, in which silicon is fourfold coordinated to oxygen. These tetrahedra can exist as isolated units or link together by sharing oxygen to create a range of structural groups, including nesosilicates (isolated tetrahedra), sorosilicates (paired tetrahedra), cyclosilicates (rings of tetrahedra), inosilicates (single or double chains), phyllosilicates (sheets), and tectosilicates (three-dimensional frameworks). Examples span the spectrum: olivine represents nesosilicates, beryl is a cyclosilicate, micas and clays are phyllosilicates, and feldspars and quartz are tectosilicates.

Occurrence and uses: Silicates are the predominant minerals in the Earth's crust and are central to geology and volcanology. They form major rock-forming minerals such as quartz and feldspars and are also important in industrial applications. Calcium, sodium, potassium, magnesium, iron, and aluminum silicates are used in cement, ceramics, glass, and various chemical industries. Silicon, derived from silicates, is essential for electronics and solar technologies.

Terminology: The term silicat (or silicate) covers both natural silicate minerals and synthetic silicate compounds. Its exact meaning can vary by language, but it denotes compounds built from silicon-oxygen tetrahedra linked into diverse three- or two-dimensional structures.