Yellow tungsten oxide nano particles may be used to prepare an electrochromic material - new energy efficient building glass. Experts say that the raw material is a yellow powder, which is insoluble in water and acid, slightly soluble in HF, and soluble in hot alkali and ammonia water. The tungsten trioxide nano powder is also a wide band gap semiconductor with an optical band gap of about 2.9eV at room temperature.
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What is the structure of WO3? The ideal WO3 crystal is a perovskite structure composed of a [WO6] regular octahedron with W atoms at the center and O atoms at the six vertices of the regular octahedron. Actually, the obtained WO3 does not strictly satisfy the stoichiometric ratio, and the octahedral unit undergoes different degrees of tilting or rotation, and the tungsten atom deviates from the octahedral body center position. In other words, the crystal structure of tungsten trioxide is a distorted perovskite structure.
