Magnesium fluoride is an ionically bonded inorganic compound with the formula . The compound is a colorless to white crystalline salt that is transparent over a wide range of wavelengths, such that it is used in the optical windows of 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 ammonium bifluoride, by the breakdown of it:

:

Related metathesis reactions are also feasible:

:

Structure

The compound crystallizes as tetragonal birefringent crystals. The structure of the magnesium fluoride is similar to that of rutile, featuring octahedral cations and 3-coordinate fluoride| anions.

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|+Coordination geometry in magnesium fluoride

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! Magnesium coordination

! Fluorine coordination

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In the gas phase, monomeric molecules adopt a linear molecular geometry.

Safety

Chronic exposure to magnesium fluoride may affect the skeleton, kidneys, central nervous system, respiratory system, eyes and skin, and may cause or aggravate attacks of asthma.

References

  • Infrared windows at Lawrence Berkeley National Laboratory
  • National Pollutant Inventory - Fluoride and compounds fact sheet
  • Crystran Data Crystran MSDS