HOME

TheInfoList



OR:

Tungstic acid refers to hydrated forms of tungsten trioxide, WO3. Both a
monohydrate In chemistry, a hydrate is a substance that contains water or its constituent elements. The chemical state of the water varies widely between different classes of hydrates, some of which were so labeled before their chemical structure was understo ...
(WO3·H2O) and hemihydrate (WO3·1/2 H2O) are known. Molecular species akin to sulfuric acid, i.e. (HO)2WO2 are not observed. The solid-state structure of WO3·H2O consists of layers of octahedrally coordinated WO5(H2O) units where 4 vertices are shared. The dihydrate has the same layer structure with the extra H2O molecule intercalated. The monohydrate is a yellow solid and insoluble in water. The classical name for this acid is 'acid of wolfram'. Salts of tungstic acid are tungstates. The acid was discovered by
Carl Wilhelm Scheele Carl Wilhelm Scheele (, ; 9 December 1742 – 21 May 1786) was a Swedish German pharmaceutical chemist. Scheele discovered oxygen (although Joseph Priestley published his findings first), and identified molybdenum, tungsten, barium, hydroge ...
in 1781.Scheele, Carl Wilhelm (1781
"Tungstens bestånds-delar"
(Tungsten's .e.,_Scheelite's.html" ;"title="Scheelite.html" ;"title=".e., Scheelite">.e., Scheelite's">Scheelite.html" ;"title=".e., Scheelite">.e., Scheelite'sconstituents), ''Kungliga Vetenskaps Academiens Nya Handlingar'' (Royal Scientific Academy's New Proceedings), 2: 89–95. (in Swedish)


Preparation

Tungstic acid is obtained by the action of strong acids on solutions of alkali metallic tungstates. It may also be prepared from the reaction between hydrogen carbonate and sodium tungstate. It can also be obtained from pure tungsten by reaction with hydrogen peroxide.


Uses

It is used as a mordant and a dye in textiles.


References

Tungstates Tungstic acids Transition metal oxoacids {{inorganic-compound-stub