metalsilicates

Metalsilicates are chemical species and minerals that involve silicate units coordinated with metal cations. In inorganic chemistry, the term metasilicate most often refers to the metasilicate anion [SiO3]2−, derived from metasilicic acid H2SiO3, which forms salts with metal cations such as Na+, K+, or Ca2+. The resulting salts, for example sodium metasilicate Na2SiO3 and potassium metasilicate K2SiO3, are typically highly alkaline and find use in detergents, water treatment, and as binders and adhesives. In solution, the metasilicate ion can form polymeric species depending on concentration and pH.

In mineralogy and geology, metalsilicates can describe a class of silicate minerals in which silicon–oxygen tetrahedra link into one-dimensional chains, giving the empirical formula (SiO3)n. These chain silicates, also called inosilicates, include minerals such as wollastonite CaSiO3 and enstatite MgSiO3. In these minerals, each SiO4 tetrahedron shares two oxygens with neighbors, creating chains balanced by metal cations in the crystal lattice.

Structure and properties: Silicate chains are built from SiO4 tetrahedra, and the degree of polymerization influences physical properties such as hardness, melting behavior, and cleavage. The term metalsilicate can thus refer to both metasilicate salts and to chain-silicate minerals containing metal cations.

Applications and significance: Metalsilicate salts are important in industrial applications and materials chemistry, while metalsilicate minerals are studied in geology and planetary science to understand silicate polymerization and mantle-crust processes.

Safety: Metasilicate solutions are caustic and can irritate skin and eyes; appropriate handling and protective measures are advised.