Yellow Tungsten Oxide
Introduction
Name: Yellow Tungsten Oxide
Appearance: Yellow powder
Formula: WO3
Molar Mass: 231.85g·mol-1
Melting Point: 1473℃
Boiling Point: 1700 °C
Density:7.16 g/cm3
Solubility (Water): Insoluble
Solubility (other solvents): alkali-soluble, acid-soluble
CAS: 1314-35-8
Warning Terms: R22-R36/37/38
Safety Phrases: S26-S36
Main Hazards: May cause damage to the eyes, skin, also respiratory and digestive system
structure
It depends on the temperature: tetragonal at the temperature above 740°C; orthorhombic at 330-740°C; monoclinic at 17-330°C; triclinic at -50-17°C. Wherein the most common form is monoclinic structure with the space group is P2 1/n .
Property
The property of it is differing with different preparation conditions (speed and temperature): tungsten trioxide comes from the low temperature has more active and easy soluble in water; however it is insoluble in water when obtained from the high temperature. Furthermore, if the thermal decomposition of ammonium paratungstate is in the reducing atmosphere, the product would be blue tungsten oxide (tungsten blue, WO 3-x ), components indefinite, mainly tungsten trioxide, ammonium salts and tungsten dioxide.
Application
A large number of it is used to produce tungsten metal powder and tungsten carbide powder; section for the production of chemical products, such as paints and coatings, catalysts in the petroleum industry and so on; also can be used as a pigment in the paint and ceramics; besides, tungsten trioxide also applied in the smart windows.