CaF2s

Calcium difluoride, with the chemical formula CaF2, is an inorganic compound that forms white, transparent crystals. It occurs naturally as the mineral fluorite (fluorspar), which is found in a variety of geological environments and has long been mined for industrial use.

CaF2 crystallizes in the fluorite structure, a cubic arrangement in which calcium ions occupy tetrahedral sites within a lattice of fluoride ions. Each calcium ion is surrounded by eight fluoride ions, giving the material its characteristic isotropic properties. The compound is relatively hard for a salt, has a high melting point, and is chemically stable under ordinary conditions. It is sparingly soluble in water and reacts with strong acids to some extent, but remains resistant to many common environmental conditions.

In addition to its crystal structure, CaF2 is notable for its optical properties. It transmits a broad range of wavelengths, from the vacuum ultraviolet to the mid-infrared (approximately 125 nm to 9 μm), with a low refractive index around 1.43 at visible wavelengths and low dispersion. These properties make CaF2 a favored material for ultraviolet and infrared optics, including lenses, windows, and prisms used in spectroscopy and laser systems. The material is also used in specialized optical coatings and in certain scintillation detectors when doped with rare-earth elements.

Commercially, CaF2 is obtained from fluorite ore through crushing and beneficiation, then refined for use as a flux in metallurgical processes and as a precursor for hydrofluoric acid and fluoride chemicals. Safety considerations include exposure to fluoride compounds; handling and processing require appropriate controls to prevent inhalation or tissue exposure, especially in relation to HF production or release.