Barium(2+) difluoride
Barium fluoride is a fluoride of barium that occurs naturally as the mineral frankdicksonite. It is used to make optical components such as lenses, in to production of welding agents, and in aluminum refining. Barium fluoride can also be used as a scintillator for the detection of X-rays and gamma rays. Barium is a metallic alkaline earth metal with the symbol Ba, and atomic number 56. It never occurs in nature in its pure form due to its reactivity with air, but combines with other chemicals such as sulfur or carbon and oxygen to form barium compounds that may be found as minerals. (L214, 408, L205)