Monoclinic tungsten trioxide is one of the crystal structure of tungsten trioxide. According to the researchers, they have studied the crystal structure of tungsten trioxide at room temperature by the X-ray oscillation method.
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And it was found that the tungsten trioxide crystal at room temperature has a monoclinic unit cell with a =7.30 ?, b =7.53 ?, c =7.68 ? and β=90°54', containing eight molecules of WO3. That is to say, the crystal structure of tungsten trioxide at room temperature is monoclinic, and the tungsten trioxide is known as monoclinic tungsten trioxide. Wherein, the length of c axis is as twice as the values reported by the other authors. The space group is P21/n. The structure analysis was performed by trial and error based on inspection of the Patterson projections along a and c axes. The arrangement of tungsten atoms is similar to the structure reported by Braekken. The positions of oxygen atoms, which had been determined hitherto mainly from packing considerations, could be obtained directly from the weak reflections with odd index. According to the obtained structure the crystal is antipolar in the directions of a, b and c axes.
