
Blue tungsten oxide (BTO), also known as tungsten blue oxide (TBO) or β-tungsten oxide, is a compound of tungsten and oxygen. The measured density of BTO is 7.15g/cm3, the density measured by X-ray is 7.16g/cm3, and the range of homogeneous phase is WO2.8975~2.9014 (1000°C). Its formula is WO3-x. BTO’s composition is very complex, which may also exist WO2, WO3 and ammonium salts. Its most common form is WO2.9. BTO is manufactured by calcination of APT under more or less reducing…