silikaty

Silikaty, in chemistry and geology, are a broad class of compounds built from silicon-oxygen tetrahedra. Each tetrahedron consists of one silicon atom surrounded by four oxygen atoms. These SiO4 units link together in various ways to form minerals and materials. Silicates are the most abundant group of minerals in Earth's crust, and they also occur as amorphous siliceous substances such as opal or glass.

The structure of silicates determines their classification. The six major groups are: nesosilicates, where tetrahedra are isolated; sorosilicates, with pairs of tetrahedra sharing a single oxygen; cyclosilicates, formed by rings of tetrahedra; inosilicates, consisting of single or double chains; phyllosilicates, arranged as sheet structures; and tectosilicates, which form three-dimensional frameworks. Common silicate minerals include feldspars, pyroxenes, amphiboles, micas, quartz, and zeolites, among many others. The variety arises from the way tetrahedra connect and the cations that balance charge.

Silikaty form through magmatic crystallization, metamorphism, and sedimentary processes. They occur in a wide range of rocks, including igneous rocks like granite and basalt, sedimentary rocks such as sandstone and shale, and metamorphic rocks like quartzite. Weathering and hydrothermal processes can transform silicates into clays and other secondary minerals.

Industrial and practical relevance is broad. Silica (SiO2) is central to glass and ceramics; feldspars and micas are used in ceramics and glassmaking; clays serve in cement, ceramics, and fillers; and zeolites function in catalysis and ion-exchange processes. Silicates also provide vital clues about the Earth’s crust and its geological history.

Health and safety considerations include the inhalation risk from crystalline silica dust, which can cause lung diseases. Proper dust control and protective measures are important in mining, milling, and fabrication.