Used in optical coatings and laser materials due to its low refractive index and high transparency in the ultraviolet and vacuum ultraviolet regions. Employed in the production of fluoride glass for fiber optics and in scintillation counters for radiation detection, including medical X-ray imaging to enhance resolution and reduce radiation exposure. Serves as a catalyst in petroleum refining and organic synthesis. Applied in solid-state devices and as a component in phosphors for lighting and display technologies. Also utilized in ceramics to improve high-temperature durability and strength, particularly for electronics in harsh environments, and in research for developing lanthanum-based ceramics and electronic materials.