CaOSiO2

CaOSiO2 is a chemical composition representing calcium oxide combined with silicon dioxide in a 1:2 ratio, often written as CaO·SiO2. In practice, it is used as a shorthand for calcium silicate materials rather than a discrete, well-established mineral. The exact binary CaO–SiO2 compound is not widely recognized as a stable, separate phase under ordinary conditions; instead, calcium silicates in this region of composition occur as various crystalline phases or as glassy/ceramic materials.

Structure and properties of calcium silicate systems depend on synthesis and temperature. Crystalline calcium silicate minerals such as wollastonite (CaSiO3) illustrate related stoichiometries, but CaO·SiO2 itself is more commonly encountered as part of a broader silicate network. In glass or ceramic formulations, CaO–SiO2 compositions form a network of silicon-oxygen tetrahedra with calcium as a network modifier, contributing to properties such as refractoriness and chemical durability. The material generally exhibits high melting points and varying hardness and density depending on phase and microstructure.

Synthesis typically involves high-temperature reaction of calcium oxide with silicon dioxide. In cement chemistry, calcium silicate phases play a crucial role in hydration products, especially in the formation of calcium silicate hydrates and related phases that contribute to the strength development of cement paste. CaOSiO2-related formulations also appear in ceramics and refractory materials where thermal stability is important.

See also: wollastonite (CaSiO3), diopside (CaMgSi2O6), merwinite (Ca3MgSi2O8), calcium silicate hydrates (C-S-H), cement chemistry. Safety considerations follow those for calcium oxide and silica in powder form; handle with appropriate protective equipment to avoid inhalation or caustic exposure.