calcium fluoride CaF2
The chemical formula of calcium fluoride is CaF2. Colorless crystal or white powder; hardly soluble in water, slightly soluble in inorganic acid; reacts with hot concentrated sulfuric acid to generate hydrofluoric acid. The experiment generally uses calcium carbonate and hydrofluoric acid to react or repeatedly treat fluorite powder with concentrated hydrochloric acid or hydrofluoric acid to prepare calcium fluoride. Calcium fluoride minerals in nature are fluorite or fluorspar, often in gray, yellow, green, purple and other colors, sometimes colorless, transparent, glassy luster, brittle, and significant fluorescence. Very pure fluorspar is used to make special lenses. Fluorite is mainly used as a flux for smelting metals; when the drinking water contains 1-1.5ppm calcium fluoride, it can prevent dental diseases.