BaSi2O5

BaSi2O5 is an inorganic compound that belongs to the family of barium silicates. Its formula reflects one divalent barium ion balanced by two silicate units, and it is studied primarily in the context of BaO–SiO2 glass-ceramic systems where BaSi2O5 can crystallize as a disilicate phase.

Structure and polymorphism: In crystalline samples, BaSi2O5 forms a silicate network linked to Ba2+ ions. Several polymorphs have been reported, with the specific crystal structure depending on synthesis conditions and temperature. The exact coordination environment of the silicon-oxygen framework and barium ions can influence physical properties.

Synthesis and occurrence: BaSi2O5 can be prepared by solid-state reaction of barium-containing precursors, such as BaCO3, with silicon dioxide (SiO2) at elevated temperatures, typically well above 1000°C. It also appears as a crystallized phase in BaO-SiO2 glass-ceramics during controlled heat treatment, where it contributes to the material’s microstructure.

Properties: BaSi2O5 is a refractory silicate, exhibiting high thermal stability and chemical durability typical of silicate minerals. It is insoluble in water and displays properties that vary with crystal form and particle size. Specific data such as melting point or exact hardness depend on the polymorph and synthesis route.

Applications: In materials science, BaSi2O5 is investigated as a crystallization product that can affect the thermal expansion, microstructure, and optical properties of glass-ceramics. It is not a major commercial material on its own but is relevant to the design of BaO–SiO2-based ceramics and glasses.

See also: Barium silicates, disilicates, BaSiO3.