Magnesium fluoride is a white, crystalline, fluorescent mineral that is an insulator of heat and electricity. The atoms of magnesium and fluorine bond together by strong electrostatic forces. This gives the material its high melting point and boiling point.
It is an ionic compound in which magnesium donates one electron to each fluorine atom to form an ionic bond. Each ion then donates one of its valence electrons to the other to obtain an octet configuration.
MgF2 has a rutile crystal structure, melting at 1255 degC and a density of 3,148 g/cm3. It is insoluble in water but soluble in nitric acid.
It has a high refractive index and is used in optical applications such as lenses and windows. It has a very long lifetime and is resistant to UV and IR radiation.
The spectra of room temperature-deposited MgF2 show absorption bands at 3 and 6 um, which may be related to the presence of voids in its microstructure. When vented to room air, these voids are dissolved and the film shifts its wavelength.
Materion has developed a manufacturing process for magnesium fluoride that produces a highly pure, dense material form. It is deposited on glass or Zinc Sulfide substrates and evaporates cleanly, completely, without outgassing or spitting, and leaves a hard, uniform coating on the surface of the substrate.