Lanthanum Fluoride or lanthanum trifluoride, is a high-melting, white powdered inorganic compound composed of fluoride and the rare earth lanthanum. It is insoluble in water, hydrochloric, nitric, sulfuric acids, but can be dissolved in perchloric acid. It is mainly applied in specialty glass, water treatment and catalyst. It is also the main material in making lanthanum metal. This specialty glass, called ZBLAN, has superior transmittance in the infrared range and is therefore used for fiber-optical communication systems. Lanthanum Fluoride is also used in phosphor lamp coatings.