Gallium Chloride synthesis
Dhiresh Shah
200 degrees. Hcl gas is dried by passing it through Sulphuric acid and
Anhydrous Cacl2. After Ga has reacted with Hcl gas, the tube is cooled
off and nitrogen gas is passed through the glass tube. The whole
reaction is carried out in a fume cupboard.
The problem is instead of getting a white crystalline solid, I get a lot
of creamy liquid. And when I open the glass tube in a fume cupboard, the
little white solid formed turns to creamy liquid. Gacl3 is air sensitive
and moisture sensitive.
Can anybody guide me on the abovr experiment? Your advice would be
highly appreciated.
Uncle Al
Does gallium get naughty with subchlorides? Gaseous HCl is not like HCl
in water.
Why don't you make hydrated gallium chloride in the obvious manner, then
dehydrate it by refluxing with with thionyl chloride, then pump off
excess SOCl2? Or use chlorine diluted in an argon stream in your
apparatus.
Does GaCl3 vapor transport under your synthetic conditions?
Why don't you BUY the stuff, Aldrich or Alfa?
--
Uncle Al Schwartz
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Don Wilkins
wrote:
>I am trying to make Gacl3 by passing Hcl gas over Ga in a glass tube at
>200 degrees. Hcl gas is dried by passing it through Sulphuric acid and
>Anhydrous Cacl2.
I would eleiminate the CaCl2.
> After Ga has reacted with Hcl gas, the tube is cooled
>off and nitrogen gas is passed through the glass tube. The whole
>reaction is carried out in a fume cupboard.
I am surprised that this doesn't produce GaCl2 instead of GaCl3 but
presume that you have considered that.
Many years ago I was assigned the prep of FeCl3 in an inorganic
synthesis course. As I recall if one started with iron metal and used
HCl the product was FeCl2 and if one used Cl2 then one obtained FeCl3.
At any rate the prep I used had a glass tube with some constrictions
to give a long pyrex tube which looked like a snake had swallowed some
rabbits.
The iron went in the first bulge and the Cl2 (dried passing through
H2SO4) formed FeCl3 in that section. Purification was accomplished by
subliming the FeCl3 to subsequent sections using the stream of Cl2 to
encourage the vapor to move downstream. Gory details of the first few
attempts not discussed here.
I believe there is a prep for AlBr3 in Inorganic Synthesis Volume III
page 30. My reference states that this is a typical procedure for the
trihalides of this group. I would suggest that you check that
reference and also poke around the other volumes to see if there is a
prep for GaCl3. If you find a prep in Inorganic Synthesis the chances
are good that it will work.
Also there was some work in the 40's studying properties of GaCl3. If
the above reference doesn't get you on the right track try some of
those references. If they studied it they must have made it.
I am still having difficulty thinking about getting GaCl3 from the
metal and HCl.
>The problem is instead of getting a white crystalline solid, I get a lot
>of creamy liquid. And when I open the glass tube in a fume cupboard, the
>little white solid formed turns to creamy liquid. Gacl3 is air sensitive
>and moisture sensitive.
You can't open these in air. Seal off your tube on one end, pull a
vacuum, and seal the product. You will probably need to work in a
drybox to handle the material.
>Can anybody guide me on the abovr experiment? Your advice would be
>highly appreciated.
Advice is worth what you pay for it. I don't charge.