Blue tungsten oxide refers to a class of dark blue compounds containing tungsten in mixed valence states of tungsten (VI) and tungsten (V). It is characterized by its dark blue powder appearance. Molecular formula: WO2.9.
The composition of blue tungsten is very complex, including intermediate oxides such as WO2 and W4. If blue tungsten is calculated by its composition as WO3, the tungsten content is 82.13%, whereas the tungsten content in WO3 is 79.30%. Pertanto, the tungsten content in blue tungsten oxide is greater than in tungsten trioxide.