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Tungsten has several oxidation states, and therefore oxides: Tungsten(III) oxide; Tungsten(IV) oxide, also known as tungsten dioxide; Tungsten(VI) oxide, also known as tungsten trioxide; Tungsten pentoxide
Tungsten(IV) oxide is the chemical compound with the formula W O 2. The bronze-colored solid crystallizes in a monoclinic cell. [1] The rutile-like structure features distorted octahedral WO 6 centers with alternate short W–W bonds (248 pm). [1] Each tungsten center has the d 2 configuration, which gives the material a high electrical ...
Tungsten(VI) oxide, also known as tungsten trioxide is a chemical compound of oxygen and the transition metal tungsten, with formula WO 3. The compound is also called tungstic anhydride , reflecting its relation to tungstic acid H 2 WO 4 .
The relative rarity of tungsten(III), for example, contrasts with the pervasiveness of the chromium(III) compounds. The highest oxidation state is seen in tungsten(VI) oxide (WO 3). [61] Tungsten(VI) oxide is soluble in aqueous base, forming tungstate (WO 4 2−). This oxyanion condenses at lower pH values, forming polyoxotungstates. [62]
Tungsten(III) oxide (W 2 O 3) is a compound of tungsten and oxygen. It has been reported (2006) as being grown as a thin film by atomic layer deposition at temperatures between 140 and 240 °C using W 2 (N(CH 3 ) 2 ) 6 as a precursor. [ 1 ]
Tungsten(VI) fluoride, also known as tungsten hexafluoride, is an inorganic compound with the formula W F 6. It is a toxic, corrosive, colorless gas, with a density of about 13 kg/m 3 (22 lb/cu yd) (roughly 11 times heavier than air). [2] [3] It is the densest known gas under standard ambient temperature and pressure (298 K, 1 atm). [4]
Scheelite is a calcium tungstate mineral with the chemical formula Ca W O 4. It is an important ore of tungsten (wolfram). Scheelite is originally named after Swedish chemist Carl Wilhelm Scheele (1742–1786). Well-formed crystals are sought by collectors and are occasionally fashioned into gemstones when suitably free of flaws.
Nickel tungstate can also be prepared by the reaction of nickel(II) oxide and tungsten(VI) oxide. [6] It can also be obtained by the reaction of ammonium metatungstate and nickel(II) nitrate [7] or from the reaction of sodium tungstate, nickel(II) chloride and sodium chloride. [8] Nickel tungstate undergoes a phase transition at 700°C. [5]