Tungsten bronze is a kind of non-stoichiometry compound, it has chemical inertness. The tungsten bronzes are a group of compounds made up of tungsten trioxide, WO3, and an alkali metal, such as sodium (Na), potassium (K), rubidium (Rb), or cesium (Cs). The general chemical form is MxW03, where M=Na, K, Rb, or Cs, and 0< x< 1. The color of these compounds varies with composition, at x=0.93 the color is a bronzelike golden-yellow; at x=0.32 the color is blue violet.
Cesium tungsten oxide (CsxWO3) is a kind of functional compound which has nonstoichiometry ratio and oxygen octahedral, it has low electrical resistivity and low temperature superconducting property. CsxWO3 is discovered to have great near infrared shielding property which is expected to take replace of ITO as raw material for smart window, it has wide application prospect in automobile and architecture field.
Cesium tungsten bronze nano powder has good resistance. The mechanism for it to shield infrared ray is the absorbance of infrared ray by oxygen valance in the nano powder. Oxygen valance would react with moisture in the air to lower its concentration, so the insulating effect is lower down, Soaking the insulating thin film in 60℃ hot water for 168hours, the shielding rate only drops for 1.8%, it shows the cesium tungsten bronze nano powder has better moisture resistance. The service life is approximately 20 years which can largely lower the cost of thin film.
Ammonium tungsten bronze(ATB) is a kind of blue oxidation material with hexagonal or tetragonal structure which contains ammonium. If is more active than blue tungsten oxide, especially ammonium ion can interexchange with doping element—potassium. During reduction process, it will form tungsten phase structure with potassium which is helpful for potassium enters tungsten and disperse.
Potassium tungsten bronze(KxWO3) has crystalline structure for hexagonal （0.18≤x≤0.33）and tetragonal（0.40≤x≤0.59）, it has super conductive property which shows charge density waves. Color of KxWO3 changes with value of x. When x increases, it turns from dark blue(x=0.20) to purple(x=0.60).
Crystalline structure of NaxWO3 is affected by value of x. When x < 0.1, NaxWO3 is WO3 structure, it uses WO63 is tetragonal crystalline. When 0.35 < x < 1, NaxWO3 has perovskite structure with Na+ vacancy. These two crystalline structure has WO6 octahedral structure unit. Under different temperature, WO6 octahedral can flex in different directions to make the temperature change of crystalline structure. It offers the possibility of synthesis for different materials.
Hydrogen tungsten bronze(HxWO3，0≤x≤1) is non stoichiometric compound, it has ring channel and special space tunnel structure. This structure is useful for disembedding and exchange for ion, thus makes it capable of offering and accepting proton.
Lead tantalum into hexagonal tungsten oxide structure, TaxWO3 of nanowire structure is obtained, photochromatic catalytic property of material is improved, reduction ability for hydrogen ion is stable, it is expected to be applied in fuel cell field.