jkus
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Solubility of tungstic acid
From Google Serach, it appears that H2WO4 (tungstic acid) is nigligibly soluble in water. (Exception:HF)
It only dissolves in concentrated solutions of alkali hydroxides and in ammonia.
I am in dilemma which alkali hydroxide is to be used?
Because I want that alkali hydroxide volatile. I mean it should be thermally decomposible.
Need suggestion.
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Pyridinium
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tungstic acid will dissolve in aqueous ammonia, which is volatile, but it will form ammonium paratungstate.
Thermal decomposition of this will give yellow tungsten oxide, blue tungsten oxide, or ammonium tungsten bronze depending on the conditions.
You could crystallize out the ammonium paratungstate and let the solution evaporate without heating.
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jkus
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Well,
Thats true.
What I want to do is to prepare thin films of WO3 by spray pyrolysis (thermal decomposiiotn) onto the glass substrates.
Then I want to deposit composite TiO2/WO3 thin films by the same technique. I have already prepared TiO2 thin films from methanolic solution. Now to
prepare Composite film, it is necessary that the precursors of TiO2 and WO3 should have one common solvent in which they could dissolve completely. So
I need non-aqueous solvent.
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not_important
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SFAIK you're pretty much limited to
A) Instead of ammonia, using an amine with a large enough organic chain that it will drag the tungsten portion into an organic solvent; the carbon
may cause problems for your goals.
B) Use WCl6 in ether or chloroform
C) Use a tungsten alkoxide, such as the ethoxide made from WCl6 and ethanol, and let it hydrolise. This is the typical method used to get tungsten
oxide films, there are numerous articles and patents on the subject.
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jkus
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Thanks a lot for the information, the much needed.
Could u please suggest me these references, please, if possible.
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not_important
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just use Teh Google on 'tungsten ethoxide'
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Levi
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Why is this in the energetic materials section? I'm not finding anything online to suggest that this is an energetic substance or a useful precursor.
From his stated goal I assume he wants to make his own capacitors, in which case technochemistry would be more appropriate.
Chemcrime does not entail death. Chemcrime is death.
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chemisttree
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| Quote: | Originally posted by not_important
SFAIK you're pretty much limited to
A) Instead of ammonia, using an amine with a large enough organic chain that it will drag the tungsten portion into an organic solvent; the carbon
may cause problems for your goals.
B) Use WCl6 in ether or chloroform
C) Use a tungsten alkoxide, such as the ethoxide made from WCl6 and ethanol, and let it hydrolise. This is the typical method used to get tungsten
oxide films, there are numerous articles and patents on the subject. |
I would recommend the sol-gel route that Not-important recommends. There is a lot of information that will help you.
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Eclectic
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Both Ti and W are soluble in acidic peroxide aqueous solutions.
There are also some really soluble heteropoly acids of tungsten, maybe some even incorporating Ti that might be useful for a H20 based method.
H4(WO3)12SiO4 , AFAIK, is the formula for dodecasilicotungstic acid.
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