silikaat

Silikaat, or silicate, refers to a broad class of minerals and compounds that contain silicon and oxygen as a fundamental building block, typically combined with various metals. The essential structural unit is the silicate tetrahedron (SiO4), where silicon is surrounded by four oxygen atoms. These tetrahedra can link together in different ways, producing a wide range of silicate minerals with varying chemistries, colors, and physical properties.

Silicate minerals are traditionally classified by how the tetrahedra are polymerized: nesosilicates (isolated tetrahedra), sorosilicates (paired tetrahedra), cyclosilicates (ring structures), inosilicates (single or double chains), phyllosilicates (sheets), and tectosilicates (frameworks). Examples include: olivine (nesosilicate), quartz (tectosilicate), feldspars (tectosilicates), micas (phyllosilicates), pyroxenes and amphiboles (inosilicates), and borosilicate rings such as beryl (cyclosilicate). This structural diversity accounts for the wide range of physical properties observed in silicates.

Occurrence and formation: Silicate minerals are the dominant constituents of the Earth’s crust and mantle. They form through magmatic crystallization, metamorphic transformations, alteration of rocks, and sedimentary processes. Their abundance and variety underlie many geological processes and the overall chemistry of soils and rocks.

Uses and significance: Silicates are essential in industry and everyday life. They are the primary raw materials for cement and glass, ceramics, refractories, and numerous consumer products. Silica, in crystalline or amorphous form, is also used in filtration, catalysis, and as a desiccant. In occupational settings, inhalation of crystalline silica dust poses health risks and is subject to safety regulations.