Oxygen index reflects the oxygen numbers range of blue tungsten oxide. Oxygen index is important information, and its size reflects the tungsten content in products. The lower the oxygen index is, the higher is the tungsten content.
Determination of oxygen index in blue tungsten oxide is as follows:
Blue tungsten oxide can dissolve in potassium hydroxide and product K2WO4 with potassium ferricyanide solution. Excess potassium ferricyanide in acidic solution reacts with potassium iodide and release iodine. Titrate with standard solution of sodium thiosulfate and calculate the oxygen index of blue tungsten oxide.