Ca2Al2Si2O7F2

Ca2Al2Si2O7F2 is the chemical formula for a mineral that belongs to the melilite group. This mineral is characterized by its specific arrangement of calcium, aluminum, silicon, oxygen, and fluorine atoms. The melilite group itself is a series of solid solutions with a general formula (Ca,Na)2(Al,Mg,Fe)3(Si,Al)3O7. Ca2Al2Si2O7F2 is a fluorinated end-member of this group, meaning it has a high proportion of fluorine in its structure.

This compound is found in certain geological environments. Its formation is typically associated with conditions involving high temperatures and specific chemical compositions, often in igneous rocks or metamorphosed rocks. The presence of fluorine can influence the mineral's properties and its stability under different conditions.

In terms of physical properties, Ca2Al2Si2O7F2, like other melilites, is generally a relatively soft mineral with a Mohs hardness typically around 5-6. It is often found as prismatic or tabular crystals. Its color can vary depending on impurities, but pure forms tend to be colorless or white. The specific optical properties, such as refractive indices and birefringence, are determined by its crystal structure and chemical composition. Scientific research on this mineral focuses on its crystallography, its occurrence in various rock types, and its behavior under different physical and chemical conditions. Its fluorinated nature distinguishes it within the broader melilite family, offering insights into mineral formation processes.