How to distinguish WO3 and WO2?

There are four stable tungsten oxide: yellow oxide (WO3), blue oxide (WO2.90), purple oxide (WO2.72) and tan oxide (WO2).

Tungsten trioxide is lemon-yellow crystalline powder, a density of 7.2 ~ 7.4g / cm3, melting point of about 1470 ℃, boiling point between 1700 ~ 2000 ℃, significantly higher than the sublimation 800 ℃, tungsten trioxide generate heat 202.8 cal / mol, tungsten anhydride can be slightly soluble in water (0.2g / L), insoluble in all inorganic acids other than hydrofluoric acid. Tungstate easily soluble caustic solution (NaOH or KOH) and ammonia to form tungstate [NaWO4, K2WO4 and (NH4) 2WO4]. Ammonia solution in tungsten trioxide dissolved slowly, heated to a high temperature to dissolve more slowly. Tungsten trioxide readily reduced various reducing agents. At room temperature, even small amounts of organic matter will be able to restore it, and change its color. However, time and heated in air to restore the original color. At 700 ~ 900 ℃, the tungsten trioxide is readily reduced by hydrogen, carbon monoxide and carbon into tungsten metal.

Tungsten dioxide is a chocolate powder, a density of 10.9 ~ 11.1g / cm3, a boiling point of about 1700 ℃, generate heat 134 kcal / mol, at 575 ~ 600 ℃ when the hydrogen reduction of tungsten trioxide generated tungsten dioxide. Tungsten dioxide in water, alkali solution, hydrochloric acid and dilute sulfuric acid does not dissolve. Tungsten can be oxidized to nitric oxide high oxide. Tungsten dioxide in the air quickly oxidized to tungsten trioxide, heated at 500 ℃ to turn blue in the oxide in the oxide. In 1020 ℃ into tungsten carbon dioxide can be reduced to metallic tungsten.

Tungsten Powder Manufacturer & Supplier: Chinatungsten Online - http://www.tungsten-powder.com
Tel.: 86 592 5129696; Fax: 86 592 5129797
Email: sales@chinatungsten.com
Tungsten & Molybdenum Information Bank: http://i.chinatungsten.com
Tungsten News & Tungsten Prices, 3G Version: http://3g.chinatungsten.com
Molybdenum News & Molybdenum Price: http://news.molybdenum.com.cn

• < Prev
• Next >