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Zinc selenide (ZnSe), is a light yellow binary solid compound. It is an intrinsic semiconductor with a band gap of about 2.7 eV at 25 °C. It has a standard enthalpy of formation of 177.6 kJ/mol at 25 °C. It adopts a Zincblende lattice structure with lattice constant a=566.8 picometers.
ZnSe rarely occurs in nature. It is found in the mineral stilleite named after Hans Stille.
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Applications
It is used as an infrared optical material with a remarkably wide transmission wavelength range (0.6 μm to 20 μm). The refractive index is about 2.67 at 550 nm (green), and about 2.40 at 10.6 µm (LWIR). ZnSe is sometimes called by the names Irtran-4 or Raytran as an infrared material (Raytran is a trade mark of the Raytheon company). Zinc selenide slowly reacts with atmospheric moisture, which leads to degradation of the optical surfaces when the lenses are exposed to humidity. Coated optics are available, with moisture sensitivity significantly diminished.
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Chemistry
ZnSe reacts with acids to form toxic hydrogen selenide gas.
It is grown by chemical vapour deposition techniques including MOVPE.
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See also
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