text: Magnesium fluoride is an ionically bonded inorganic compound with the formula . The compound is a white crystalline salt and is transparent over a wide range of wavelengths, with commercial uses in optics that are also used in space telescopes. It occurs naturally as the rare mineral sellaite.
  Production
  Magnesium fluoride is prepared from magnesium oxide with sources of hydrogen fluoride such as can be obtained from the breakdown of ammonium bifluoride:
  Related metathesis reactions are also feasible: