Oxysilicates

Oxysilicates are chemical compounds in which silicon is bonded to oxygen to form silicate units that can exist as discrete ions, chains, sheets, or three‑dimensional networks. The core motif is the SiO4 tetrahedron, with silicon in the +4 oxidation state. In oxysilicates, these tetrahedra connect through shared oxygen atoms and are balanced by metal cations, hydrogen, or other counterions. The term often encompasses a wide range of silicate materials, from minerals to synthetic glasses and ceramics.

Structurally, oxysilicates are classified by how the SiO4 units link together. Nesosilicates (isolated SiO4 units) provide discrete tetrahedra, as in olivine. Inosilicates form single chains (SiO3) or double chains, cyclosilicates create rings (Si_nO_3n), and tectosilicates build three‑dimensional frameworks (e.g., SiO2 in quartz). The degree of polymerization and the connectivity of the tetrahedra determine properties such as hardness, melting point, and chemical durability. In many discussions, the term oxysilicate is used broadly to describe silicate materials whose anionic framework consists mainly of silicon–oxygen units, with the overall composition balanced by other cations.

Occurence and applications include geology and materials science. Oxysilicates constitute most silicate minerals, including quartz and feldspars, as well as the olivine family. In industry they are central to glass, ceramics, cementitious systems, and geopolymer materials. Synthesis is achieved by high‑temperature solid‑state reactions, hydrothermal methods, or sol–gel processing. Characterization commonly employs X‑ray diffraction, infrared spectroscopy, and electron microscopy.

See also: silicate minerals, orthosilicates, metasilicates, silicate networks.