Magnesium Oxide – MgO

lenses, windows, mirrors, filters and prisms

Magnesium oxide is physically and chemically stable at high temperatures. It has high thermal conductivity and low electrical conductivity and is used extensively in the refractory industry. It has an intermediate refractive index and a wide range of transmission that is useful for coating application from DUV to IR spectral range.

Magnesium oxide films facilitate adhesion for a number of oxides and fluorides on mineral glasses and typical IR substrates and for pyroelectric thin films, super high temperature crucibles, window material for super high temperature furnaces and optical materials for the precision optics industry.


Transmission Range 0.25 – 8.5 µ
Crystal Structure Rock Salt
Cleavage Plane 100
Colour colourless
Density 3.576 (25°)
Melting Point (°) 2800
Reflection Loss 11.6% (4µ) for 2 surfaces
Solubility index Insoluble
Hardness (Knoop) 692.0
Thermal Conductivity (cal/cm sec°C) 6×10-2 (20°C)
Thermal Expansion coefficient (/°C) 13.8×10-6(20-1000°C)


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