MgF2

Magnesium fluoride (MgF2) is an inorganic compound composed of magnesium ions (Mg2+) and fluoride ions (F−). It is a white, odorless crystalline solid with a high melting point and a molar mass of about 62.305 g/mol.

MgF2 crystallizes in a tetragonal structure related to rutile. It is virtually insoluble in water and exhibits strong chemical resistance. Its high thermal stability and durability contribute to its usefulness in demanding environments.

Optically, MgF2 is notable for broad transmission from the ultraviolet through the visible spectrum and into the infrared. It has a relatively low refractive index in the visible range (around 1.38) and is birefringent, properties that are exploited in certain optical applications such as waveplates and lenses.

In nature, MgF2 occurs as the mineral sellaite. Industrially, it is produced by fluorinating magnesium compounds with fluorinating agents (such as fluorine-containing reagents or HF) to yield MgF2, which is then purified and grown into crystals as needed.

The primary use of MgF2 is in optics. It serves as a material for ultraviolet–visible–infrared optical components, including anti-reflective coatings, UV-transparent windows, and laser optics, due to its broad transmittance and chemical stability. It is also used in specialized coatings and as a protective window material in certain scientific instruments. Safety considerations include handling of fine powders to avoid inhalation and following standard inorganic chemical precautions.