Violet Tungsten Oxide Molecular Graph
From violet tungsten oxide molecular structure graph we can see there are two different structures, one is tungsten ion closed to 6 oxygen ions, tungsten ion is in the center, it is called octahedral structure. The other is decahedron structure, tungsten ion is closed to seven oxygen ions, tungsten ion stays in the middle.
Ideal crystalline structure of tungsten trioxide (WO3) is octahedral, violet tungsten oxide has oxygen vacancy, so it has special property.