Silicaatstructuren

Silicaatstructuren refer to the diverse arrangements of silicon and oxygen atoms that form the backbone of silicate minerals, the most abundant mineral group in the Earth's crust. These structures are based on the fundamental building block, the silicon-oxygen tetrahedron, where a silicon atom is covalently bonded to four oxygen atoms. The negative charge of this tetrahedron is typically balanced by cations such as magnesium, iron, aluminum, or alkali metals.

The classification of silicate minerals is primarily determined by how these tetrahedra link together. In nesosilicates (orthosilicates), the tetrahedra exist as isolated units. Sorosilicates feature pairs of tetrahedra sharing a single oxygen atom. Cyclosilicates form rings of interconnected tetrahedra. Inosilicates exhibit chains of tetrahedra, which can be single chains (pyroxenes) or double chains (amphiboles). Phyllosilicates are characterized by sheets of tetrahedra, with common examples including micas and clays. The most complex structures are found in tectosilicates (framework silicates), where tetrahedra form a three-dimensional network, such as in quartz and feldspars. The specific arrangement of these silica-oxygen units profoundly influences the physical and chemical properties of the resulting minerals, including their hardness, cleavage, and melting point.