Blue Tungsten Oxide Molecular Graph

Blue tungsten oxide molecular graph is a kind of tungsten trioxide crystal with oxygen defect mode, the ideal structure tungsten trioxide is ReO₃ structure which is consisted with eight tungsten ion and 24 oxygen ion, namely WO₆ octahedral.

Blue tungsten oxide has very complicate composition, among them there are middle oxides of WO₂ and WO₄. Blue tungsten oxide if calculated with its its composition of WO_2.9, then tungsten content is 82.13%, while the tungsten content in WO₃ is 79.30%, that is to say tungsten content in blue tungsten oxide is more than tungsten trioxide. According to the standards of blue tungsten oxide product, its purity is suggested to be 99.95%, and among them the content of tungsten should reach 80.00% ~ 80.80%.

With the increasing of oxygen vacancy concentration, the distortion of WO₆ octahedral becomes exacerbated, and eventually leading to defects from disorderly to orderly development and make WO₆ octahedral structure change, thus the connection between cells will be changed from the previous point connection to edge connection and to form surface defect, which is known as crystallographic shear; this kind of surface defect will gradually turn to WO_2.9 with the increasing of x in WO_3-x. Single crystal of WO_3-x can be changed and showed metallicity and semiconductor according to its internal oxygen hole concentration, wherein the semiconductor WO_3-x has the forbidden band width of among 2.4~2.8eV, moreover the decrease of energy band will lead to absorption wavelength of light blue shift.